WO2019226195A2 - Fabrication and design of composites with architected layers - Google Patents
Fabrication and design of composites with architected layers Download PDFInfo
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- WO2019226195A2 WO2019226195A2 PCT/US2018/063306 US2018063306W WO2019226195A2 WO 2019226195 A2 WO2019226195 A2 WO 2019226195A2 US 2018063306 W US2018063306 W US 2018063306W WO 2019226195 A2 WO2019226195 A2 WO 2019226195A2
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/15—Nano-sized carbon materials
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
- H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
- H01G11/22—Electrodes
- H01G11/26—Electrodes characterised by their structure, e.g. multi-layered, porosity or surface features
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
- H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
- H01G11/22—Electrodes
- H01G11/30—Electrodes characterised by their material
- H01G11/32—Carbon-based
- H01G11/34—Carbon-based characterised by carbonisation or activation of carbon
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
- H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
- H01G11/84—Processes for the manufacture of hybrid or EDL capacitors, or components thereof
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/139—Processes of manufacture
- H01M4/1393—Processes of manufacture of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
- H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
- H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/624—Electric conductive fillers
- H01M4/625—Carbon or graphite
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Definitions
- the present invention relates to composite material systems, methods of making such composite material systems, which include a structure having an architected and monolithic three-dimensional geometry and a matrix phase.
- the three-dimensional geometry may include a continuous and interconnected network of features having any variety of shapes or configurations, including curved and surface features, while the matrix phase may at least partially infiltrate the structure.
- Composite materials are comprised of one or more materials which form disordered or ordered phases and combine to provide for properties or behavior which may be different from that of the individual materials. Usually these phases are classified as reinforcement phases, with high stiffness or strength properties; or matrix phases, which fill the remaining volume and possess inferior stiffness or strength properties.
- a composite can be broadly characterized by the volume ratio between the reinforcing and matrix phases, the geometry of the phases, and the constitutive properties of each phase 1 .
- Composite materials with disordered phases may include short fibers, particles, or randomly assorted components, which do not yield a continuous reinforcing phase.
- the only continuous phase is the matrix, which infiltrates the remaining volume around the reinforcement particles.
- the matrix phase serves to distribute the load between the stiffer/stronger reinforcement particles.
- ordered-phase composite materials may include aligned long fibers (discontinuous phase) or even truss-like (continuous phase) geometries as the reinforcing phase, which are surrounded by a continuous matrix phase. Both ordered and unordered composite materials can have a mechanical response that varies from isotropic (i.e., behavior independent of the probing direction) to anisotropic (i.e., behavior dependent on material orientation).
- Carbon fiber composites are a form of ordered-phase composites that have been applied in aerospace, automotive, marine, armor, and even sporting-equipment applications. Their wide-spread use relies on their high stiffness-to-density ratio, fatigue properties, and resistance to extreme environments 2 .
- the fundamental building-blocks of a carbon fiber composite are the fibers, which compose the ordered reinforcing phase that is not continuous— the discrete fibers are only coupled through the matrix phase.
- An arrangement of fibers impregnated by a matrix phase form a two-dimensional sub- component of a carbon composite part; the lamina.
- Discontinuity and anisotropy of the carbon phase in carbon fiber composites is associated with several modes of failure.
- woven-fiber laminae have been made which increase contact between discrete fibers of a lamina 3 , albeit forming a reinforcing phase that is still discontinuous.
- Isotropy can be attained with unidirectional fiber laminae by forming a laminate; a collection of laminae of varying fiber orientations that are bonded through a matrix phase. Modifying the orientation of the fibers in each lamina will determine the degree of anisotropy of the laminate as well as the (commonly undesired) stretching-bending coupling.
- Fiber buckling in compression
- interfiber failure due to their construction, carbon fiber laminates can fail through a variety of mechanisms that include fiber buckling (in compression), interfiber failure, and interlaminar failure 4 .
- Fiber buckling is preeminent in compression loading of a lamina due to the high slenderness of the fibers in the matrix, which are otherwise unsupported in-plane.
- Interfiber and interlaminar failure occurs due to the discontinuous nature of the reinforcing phase, which relies on the matrix phase to distribute load both through-thickness and in-plane.
- the composite material systems, and methods of making the systems, provided here address these and other challenges associated with conventional composite materials, thereby providing systems and methods that are highly tunable for a wide array of applications and parameter-space requirements.
- composite material systems and methods for making composite material systems useful for a wide array of applications and which address challenges and limitations of conventional systems and methods.
- Applications for which these systems are useful include, but certainly are not limited to, aerospace (e.g., landing gear shock absorption), automotive (e.g. , brake assembly vibration mitigation), medicine (e.g., medical devices requiring particular mechanical properties), military (e.g, body armor), marine devices, and sporting-equipment.
- the systems disclosed herein are useful for impact energy mitigation and/or vibration damping.
- the disclosed systems and methods are highly tunable and deterministic, such that they may be adapted and tuned according to a desired application and set of properties.
- the composite material systems disclosed herein may include functional grading via a plurality of three-dimensional geometries continuously interconnected together.
- the composite material systems may include highly tunable and deterministic resonator features which provide for precise control and tunability of damping behavior of the composite material system.
- a composite material system comprises: a structure having an architected three-dimensional geometry; wherein said three-dimensional geometry is monolithic and deterministic; and a matrix phase; wherein said matrix phase at least partially infiltrates said structure.
- the three-dimensional geometry is a nano- or micro- architected three-dimensional geometry.
- the structure is at least 1 %, at least 2%, at least 5%, at least 10%, at least 15%, at least 20%, at least 30%, at least 50%, at least 75%, at least 90%, or preferably for some applications substantially 100% by-volume (vol.%) infiltrated by the matrix phase.
- the structure is at least 1 %, at least 2%, at least 5%, at least 10%, at least 15%, at least 20%, at least 30%, at least 50%, at least 75%, at least 90%, or preferably for some applications substantially 100% by-mass (mass%) infiltrated by the matrix phase.
- composite material systems, structures, and/or three-dimensional geometries disclosed herein may have a variety of physical and mechanical properties or embodiments, including impacting absorption and/or damping behavior, unobtainable or otherwise difficult to obtain in conventional material systems.
- the structure, the composite material system, or both is characterized by an area- normalized impact energy mitigation metric (y) selected from the range of 2x10 4 J/m 2 to 4x10 5 J/m 2 .
- the structure, the composite material system, or both is by an area-normalized impact energy mitigation metric (y) that is at least 2x10 4 J/m 2 , optionally at least 2.6x10 5 J/m 2 , or preferably for some applications at least 3.2x10 5 J/m 2 .
- the structure, the composite material system, or both is characterized by a density-normalized impact energy mitigation metric (y) selected from the range of 1 .9x10 6 J/kg to 4x10 6 J/kg.
- y density-normalized impact energy mitigation metric
- the structure, the composite material system, or both is characterized by a density-normalized impact energy mitigation metric (y) selected from the range of 1 .9x10 6 J/kg to 3.2x10 6 J/kg, preferably for some applications selected from the range of 1x10 6 J/kg to 5x10 6 J/kg, preferably for some applications selected from the range of 1x10 6 J/kg to 1x10 7 J/kg, and optionally for some applications selected from the range of 3x10 6 J/kg to 1x10 7 J/kg.
- the structure, the composite material system, or both is characterized by mitigation of impact energy having energy selected from the range of 1 J to at least 900 J.
- the structure, the composite material system, or both is characterized by a restitution coefficient that is selected from the range of 0.8 to 0.7. In some embodiments of the systems and methods disclosed herein, the structure, the composite material system, or both, is characterized by a restitution coefficient that is selected from the range of 0.8 to 0.3.
- the restitution coefficient is determined when a particle is accelerated at said structure, said particle having a diameter that is at least 10-times greater than a physical dimension of a unit cell of the structure, optionally the particle size is 7 pm to 14 pm, and said particle having a velocity selected from the range of 500 m/s to 1 100 m/s.
- the restitution coefficient corresponds to a structure having a relative density selected from the range of 8% to 26%.
- the composite material system is configured to absorb impact energy substantially via said structure. In an embodiment, the composite material system absorbs at least 20% more impact energy than absorbed by the structure alone under otherwise identical conditions.
- the structure, the composite material system, or both is characterized by at least one vibrational frequency band gap.
- the at least one vibrational frequency band gap is at least one complete vibrational frequency band gap.
- at least one vibrational frequency band gap is at least one partial vibrational frequency band gap.
- the structure, the composite material system, or both is characterized by at least one partial vibrational frequency band gap and at least one at least one complete vibrational frequency band gap.
- the at least one vibrational frequency band gap is deterministic.
- the at least one vibrational frequency band gap is within the range of 0.1 MHz to 100 MHz, preferably for some applications within the range of 0.1 MHz to 200 MHz. In some embodiments of the systems and methods disclosed herein, the at least one vibrational frequency band gap is at least one of 52 MHz to 55 MHz, 19-26 MHz, 14-21 MHz, 46-52 MHz, 1.4 MHz to 1.5 MHz, or 2.4 ⁇ 0.1 MHz. In some embodiments of the systems and methods disclosed herein, the at least one vibrational frequency band gap corresponds to the structure being exposed to a continuous vibration, a pulsed vibration, or a combination of these.
- the at least one vibrational frequency band gap is characterized by a width selected from the range of 0.1 to 200 MHz, optionally for some applications 0.1 to 100 MHz, optionally for some applications 100 Hz to 10 MHz, optionally for some
- At least one vibrational frequency band gap corresponds to frequencies relevant to ultrasonic frequencies for medical applications.
- Broad vibrational frequency band gap widths e.g., 200 MHz
- Narrow vibrational frequency band gap widths e.g., 1 MHz
- the composite material system includes broad, narrow, or both broad and narrow vibrational frequency band gap(s).
- the structure, the composite material system, or both is characterized by a damping ratio of at least 1.2%, preferably at least 3.5%, more preferably at least 7%, and still more preferably at least 9%.
- the structure, the composite material system, or both is characterized by a damping ratio of at least 1.2% to 3.5% in a longitudinal direction.
- the structure, the composite material system, or both is characterized by a damping ratio of at least 7% to 9% in a transverse direction. In an embodiment, damping ratio corresponds to the ratio between energy dissipated in a cycle and the maximum energy stored in the cycle.
- the three-dimensional geometry comprises at least one surface feature.
- Exemplary surface features include, but are not limited to, sheets, surfaces, hollow spheres, hollow ellipses, and shells.
- the three-dimensional geometry comprises at least one surface feature, wherein at least a portion of said at least one surface feature is characterized by a non-zero Gaussian curvature.
- the three-dimensional geometry comprises at least one surface feature, wherein at least a portion of said at least one surface feature is characterized by a non-zero mean curvature.
- the three-dimensional geometry comprises at least one surface feature, wherein at least a portion of said at least one surface feature is characterized by a zero mean curvature. In some embodiments of the systems and methods disclosed herein, the three- dimensional geometry comprises at least one surface feature, wherein said at least one surface feature is characterized by a non-uniform Gaussian curvature or a non-uniform mean curvature. In some embodiments of the systems and methods disclosed herein, the three-dimensional geometry comprises at least one surface feature, wherein said at least one surface feature is characterized by a non-uniform Gaussian curvature. In some embodiments of the systems and methods disclosed herein, the three- dimensional geometry comprises at least one surface feature, wherein said at least one surface feature is characterized by a non-uniform mean curvature. In some embodiments of the systems and methods disclosed herein, the three- dimensional geometry comprises at least one surface feature, wherein said at least one surface feature is characterized by a non-uniform mean curvature. In
- the three-dimensional geometry comprises at least one surface feature, wherein said at least one surface feature is characterized by a uniform Gaussian curvature or a uniform mean curvature.
- the three- dimensional geometry comprises at least one surface feature, wherein said at least one surface feature is characterized by a uniform Gaussian curvature. In some embodiments of the systems and methods disclosed herein, the three-dimensional geometry comprises at least one surface feature, wherein said at least one surface feature is characterized by a uniform mean curvature. In some embodiments of the systems and methods disclosed herein, the three-dimensional geometry comprises at least one surface feature, wherein a thickness dimension of said at least one surface feature is non-uniform throughout said at least one surface feature. In some embodiments of the systems and methods disclosed herein, the three-dimensional geometry comprises at least one surface feature, wherein a thickness dimension of said at least one surface feature is uniform throughout said at least one surface feature.
- the three-dimensional geometry is characterized as a spinodal geometry.
- the structure is
- a slope of normalized effective elastic modulus versus relative density that is selected from the range of 1 to 1 .3, optionally 1 to 1 .5, or optionally 1 to 1.35.
- the three-dimensional geometry comprises a resonator. In some embodiments of the systems and methods disclosed herein, the three-dimensional geometry is
- the resonator comprises a micro-inertia feature connected to at least one other feature of said three- dimensional geometry.
- the resonator comprises a micro-inertia feature, and wherein another feature of said three-dimensional geometry comprises said micro-inertia feature.
- the resonator comprises a cantilever beam feature and a micro-inertia feature connected to an end of said cantilever beam feature.
- a micro-inertia feature may be embedded within another feature, such as a structural member, such as a beam or a surface.
- a micro-inertia may be at nodes of a beam structure or at the hinges of a surface-based geometry.
- the structure is characterized by deterministic anisotropic impact energy absorption, for example having impact energy absorption, or an impact energy absorption metric, such as restitution coefficient, at least 1 % greater, at least 20% greater, at least 100% greater, preferably for some applications at least 1000% greater, or still more preferably for some applications at least 10000% greater along a first direction (e.g., X, Y, Z, or any direction or vector in between) than along a second direction.
- a first direction e.g., X, Y, Z, or any direction or vector in between
- the structure is characterized by
- deterministic anisotropic elasticity for example having elasticity at least 1 % greater, at least 20% greater, at least 100% greater, preferably for some applications at least 1000% greater, or still more preferably for some applications at least 10000% greater along a first direction (e.g., X, Y, Z, or any direction or vector in between) than along a second direction.
- a first direction e.g., X, Y, Z, or any direction or vector in between
- the structure is characterized by deterministic anisotropic damping, for example having damping, or a damping metric, such as damping ratio, at least 1 % greater, at least 20% greater, at least 100% greater, preferably for some applications at least 1000% greater, or still more preferably for some applications at least 10000% greater along a first direction (e.g., X, Y, Z, or any direction or vector in between) than along a second direction.
- a first direction e.g., X, Y, Z, or any direction or vector in between
- vibrations such as vibrations within a particular frequency range, such as any frequency or range described herein, may follow along a first direction (e.g., X, Y, Z, or any direction or vector in between) than along a second direction.
- vibrations such as vibrations within a particular frequency range, such as any frequency or range described herein, may follow along a first direction (e.g., X, Y, Z, or any direction or vector in between) than
- the structure exhibits vibrational Bragg scattering and the structure does not exhibit vibrational local resonance. In some embodiments of the systems and methods disclosed herein, the structure exhibits vibrational local resonance and the structure does not exhibit vibrational Bragg scattering. In some embodiments of the systems and methods disclosed herein, the structure is characterized by deterministic isotropic impact energy absorption. In some embodiments of the systems and methods disclosed herein, the structure is
- the structure is characterized by deterministic isotropic damping.
- the systems and methods disclosed herein are compatible with a wide variety of materials, or combinations of materials.
- the structure may be formed of any one or more materials compared with additive manufacturing, for example.
- the structure comprises a carbon allotrope material, a polymer, a ceramic material, a metal material, or any combination thereof. In some embodiments of the systems and methods disclosed herein, the structure comprises at least one of: a carbon allotrope material, a polymer, a ceramic material, or any combination thereof. In some embodiments of the systems and methods disclosed herein, the structure comprises at least one of: a carbon allotrope material, a polymer, a ceramic material, or any combination thereof. In some
- the structure comprises one or more carbon allotrope materials. In some embodiments of the systems and methods disclosed herein, the structure comprises at least 50% by volume of one or more carbon materials. In some embodiments of the systems and methods disclosed herein, the structure comprises a plurality of features characterized by a core that is at least 50% by volume of one or more carbon materials.
- the three-dimensional geometry is a node-free geometry.
- the structure comprises at least one hollow feature.
- the structure comprises at least one feature that is at least partially hollow, such as a hollow truss, for example.
- a spinodal geometry may comprise at least one hollow portion or feature.
- the structure is formed via additive manufacturing.
- the three-dimensional geometry comprises at least one longitudinal feature, wherein at least a portion of said at least one longitudinal feature is characterized by a non-zero curvature along a longitudinal direction of said feature. In some embodiments of the systems and methods disclosed herein, the three-dimensional geometry comprises at least one longitudinal feature, wherein said at least one longitudinal feature is characterized by a non-uniform curvature along a longitudinal direction of said feature.
- the three- dimensional geometry comprises at least one longitudinal feature having at least one cross-sectional dimension that is non-uniform along a longitudinal direction of said feature. In some embodiments of the systems and methods disclosed herein, the three- dimensional geometry comprises at least one feature having a cross-sectional shape that is non-uniform. In some embodiments of the systems and methods disclosed herein, the said three-dimensional geometry comprises at least one longitudinal feature having a longitudinal axis oriented perpendicular to a thickness direction of said structure. For example, a thickness direction corresponds to an axis along which each layer is formed in a layer-by-layer additive manufacturing process. [0027] In some embodiments of the systems and methods disclosed herein, the structure defines a three-dimensional external boundary shape; and wherein said three- dimensional geometry comprises at least one feature that intersects said boundary shape at only one or zero points of intersection.
- a three-dimensional external boundary shape defined by said structure corresponds to a shape of the composite material system.
- a three-dimensional external boundary shape defined by said structure is hollow.
- a three-dimensional external boundary shape defined by said structure may be in the form of a hollow tube, a hollow cone, a hollow ellipse, or other configuration.
- the three-dimensional geometry is an overall three-dimensional geometry comprising at least a primary three-dimensional geometry and a secondary three-dimensional geometry, wherein said primary and said secondary three-dimensional geometries are different.
- the structure may include structural functional grading of three- dimensional geometries, such that the structure includes a plurality of geometries at least two of which are directly continuous and interconnected, and all of which are directly or indirectly continuous and interconnected.
- the structure may include compositional functional grading. Via structural functional grading (i.e.
- the structure or composite material system may have functional grading of impact energy absorption behavior and/or damping behavior.
- the matrix phase comprises at least a primary matrix phase and a secondary matrix phase.
- a first portion of the structure may be infiltrated by a primary matrix phase and a second portion of the structure may be infiltrated by a secondary matrix phase.
- the primary and secondary matrix phases may be different.
- the primary and secondary matrix phases may have different compositions.
- the primary matrix phase may be a different polymer or resin than the second matrix phase.
- the structure comprises a closed region that is free of said matrix phase.
- the structure is enclosed within said matrix phase.
- the structure is enclosed within said matrix phase such that no portion of said structure exists beyond external boundaries of said matrix phase.
- At least a portion of said three-dimensional geometry is characterized as a tetrakaidecahedron, Weaire-Phelan geometry, honeycomb geometry, auxetic geometry, an octet-truss geometry, an octahedron, a diamond lattice, a 3D kagome geometry, a tetragonal geometry, a cubic geometry, a tetrahedron, a space-filling polyhedron, a periodic minimal surface, a triply periodic minimal surface geometry, a spinodal geometry, a chiral geometry, or a combination of these.
- At least a portion of said three-dimensional geometry is characterized as a tetrakaidecahedron, auxetic geometry, an octet-truss geometry, an octahedron, a diamond lattice, a 3D kagome geometry, a tetragonal geometry, a cubic geometry, a tetrahedron, a space-filling polyhedron, a periodic minimal surface, a triply periodic minimal surface geometry, a spinodal geometry, a chiral geometry, or a combination of these when viewing the three-dimensional geometry in a beam-based, shell-based, open-cell-based, or closed-cell-based representation.
- At least a portion of said three-dimensional geometry is characterized by a beam- or shell-based geometry; wherein said beam- or shell-based geometry is not symmetric, is not periodic, or is not regularly tessellated.
- features comprise one or more of struts, beams, ties, trusses, sheets, surfaces, spheres, ellipses, and shells.
- the three-dimensional geometry is characterized by a plurality of features independently having physical dimensions independently selected to a tolerance within 100 nm. In some embodiments of the systems and methods disclosed herein, the three- dimensional geometry is characterized by a plurality of features independently having physical dimensions independently selected to a tolerance within 3 pm. In some embodiments of the systems and methods disclosed herein, the structure is
- the structure is characterized by a relative density selected from the range of 5% to 99.9%, optionally 5% to 60%, optionally 0.1 % to 60%, optionally 0.1 % to 99.9%, or optionally 8% to 30%. In some embodiments of the systems and methods disclosed herein, the structure is characterized by a relative density selected from the range of 8% to 60%. In some embodiments of the systems and methods disclosed herein, the structure is
- the three- dimensional geometry is characterized by a plurality of features independently having at least one physical dimension less than or equal to 50 pm, optionally selected from the range 100 to 200 pm.
- the three- dimensional geometry is characterized by a plurality of features, wherein at least a portion of said features independently have one or more average cross sectional physical dimensions (e.g., thickness, width, diameter, etc.) selected over the range of 50 nm to 200 pm, preferably for some applications 2 nm to 200 pm, preferably for some applications 10 nm to 200 pm, optionally 50 pm or less, optionally 200 nm or less, or optionally selected from the range 100 pm to 200 pm.
- average cross sectional physical dimensions e.g., thickness, width, diameter, etc.
- a spinodal geometry may be substantially hollow including walls or shells with substantially 10 nm thickness.
- the structure may comprise a hollow feature, such as a hollow beam or truss, having an inner diameter and an outer diameter, such that a cross-sectional physical dimension is a thickness— or difference between the inner and outer radii— or an overall thickness or diameter of the feature, such as a beam or truss.
- an inner radius may be substantially 250 nm and an outer radius may be substantially 900 nm.
- at least a portion of said features are characterized by one or more average longitudinal physical dimensions selected over the range of 10 nm to 2000 pm.
- the three-dimensional geometry is
- the unit cell characterized by a unit cell geometry, the unit cell having at least one overall physical dimension selected from the range of 10 nm to 20 pm, optionally 100 nm to 20 pm, optionally 1 pm to 20 pm, optionally 5 pm to 20 pm, or optionally 1 pm to 200 pm.
- the unit cell may have a tetragonal geometry with length, width, and thickness of 20 pm, 20 pm, and 5 pm.
- the composite material system comprises at least one additional phase.
- an additional phase is a void or a region free of the structure and of the matrix phase.
- the structure, the matrix phase, or both comprises adhesion-promoting additive(s).
- adhesion-promoting additives increase adhesion between the structure and the matrix phase compared to adhesion without said additives.
- Additives may be present during formation of the structure, such as being present in a precursor material during additive manufacturing of the structure. Additives may be deposited onto the structure after the structure is at least partially formed. Additives may be introduced during infiltration of the structure with the matrix phase. Additives may be added to a matrix phase or matrix phase precursor prior to infiltration.
- the structure is characterized by an elasticity, said elasticity of said structure being deterministic.
- the structure is substantially undamaged by impact from an Si0 2 particle having a diameter selected from the range of 7 pm to 14 pm and a velocity selected from the range of 500 m/s to 1 100 m/s.
- the structure is substantially undamaged by impact from an Si0 2 particle having a diameter that is at least one order-of-magnitude (at least 10 times) larger than an overall dimension of the unit cell characterizing the structure’s three-dimensional geometry.
- the structure is characterized as having a bending-dominated mode. In some embodiments of the systems and methods disclosed herein, the structure is characterized as having a stretching-dominated mode.
- the structure is characterized by an average specific strength (strength-to-density ratio) selected from the range of 0.14 to 1.90 GPa g -1 cm 3 . In some embodiments of the systems and methods disclosed herein, the structure is characterized by an average density selected from the range of 0.24 to 1 .0 g cm -3 . In some embodiments of the systems and methods disclosed herein, the structure is characterized by an average Young’s modulus selected from the range of 0.16 to 18.6 GPa. In some embodiments of the systems and methods disclosed herein, the structure is characterized by an average Young’s modulus selected from the range of 0.16 to 440 GPa. In some embodiments of the systems and methods disclosed herein, the structure is characterized by a compressive strength selected from the range of 5 MPa to 20 GPa. In some
- the structure is characterized by a strain-to-failure value of greater than or equal to 20%. In some embodiments of the systems and methods disclosed herein, the structure is
- the carbon allotrope material is selected from the groups consisting of glassy carbon, graphitic carbon, amorphous carbon, pyrolytic carbon, graphite, carbon black, and any combination thereof. In some embodiments of the systems and methods disclosed herein, the carbon allotrope material comprises pyrolytic carbon.
- the structure comprises a coating.
- the coating comprises a metal, a ceramic, or a combination thereof.
- the matrix phase comprises one or more material selected from the group consisting of a polymer, an epoxy, a carbon allotrope, a ceramic, a metal, a viscous fluid, or any combination thereof.
- a method of making a composite material system comprising steps of: preparing a structure via an additive manufacturing process; wherein: said structure has an architected three-dimensional geometry; and said three- dimensional geometry is monolithic and deterministic; and infiltrating said structure with a matrix phase such that said structure is at least partially infiltrated by said matrix phase; thereby making said composite material system.
- the structure is at least 1 %, at least 2%, at least 5%, at least 10%, at least 15%, at least 20%, at least 30%, at least 50%, at least 75%, at least 90%, or preferably for some applications substantially 100% by-volume infiltrated by the matrix phase.
- the structure is at least 1 %, at least 2%, at least 5%, at least 10%, at least 15%, at least 20%, at least 30%, at least 50%, at least 75%, at least 90%, or preferably for some applications substantially 100% by-mass infiltrated by the matrix phase.
- the three- dimensional geometry is a nano- or micro- architected three-dimensional geometry.
- the method further comprises designing said three-dimensional geometry using a computer-aided design technique.
- the step of designing comprises determining said three-dimensional geometry based on computational spinodal decomposition.
- the step of designing comprises determining at least one vibrational frequency band gap of said structure, such that said at least one vibrational frequency band gap of said structure is
- the step of designing comprises determining an elasticity of said structure, such that said elasticity of said structure is deterministic. In some embodiments, the step of designing comprises determining a restitution coefficient of said structure, such that said restitution coefficient of said structure is deterministic. In some embodiments, the step of designing comprises determining an area-normalized impact energy mitigation metric (y) of said structure, such that said area-normalized impact energy mitigation metric (y) of said structure is deterministic. In some
- the additive manufacturing process is selected from the group consisting of: a sterolithographic (SLA) technique; a digital light processing (DLP) technique; a continuous liquid interface production technique; a micro- stereolithographic (m-SLA) technique; a two- photon polymerization lithography technique; an interference lithography technique; a holographic lithography technique; a stimulated emission depletion (STED) lithography technique; other vat photopolymerization technique; a material extrusion technique; a powder bed fusion technique; a material jetting technique; and a combination of these.
- the additive manufacturing process is selected from the group consisting of: a sterolithographic (SLA) technique; a digital light processing (DLP) technique; a continuous liquid interface production technique; a micro- stereolithographic (m-SLA) technique; a two- photon polymerization lithography technique; an interference lithography technique; a holographic lithography technique; a stimulated emission depletion (STED)
- manufacturing process is a three-dimensional lithography technique.
- the step of preparing said structure comprises forming a three- dimensional framework; said step of preparing further comprising treating said three- dimensional framework to prepare said structure; said step of treating comprising a pyrolysis process.
- the method further comprises applying a coating on said structure.
- the method further comprises etching a portion of said structure such that said structure comprises at least one hollow feature, at least a portion of said at least one hollow feature comprising said coating.
- the step of infiltrating comprises a process selected from the group consisting of sonication, vacuum exposure, and any combination thereof.
- the method further comprises post-treating said composite material system, said step of post-treating comprising a cure process.
- the step of preparing comprises selecting a precursor material selected from the group consisting of a resin, a metal, a ceramic, a polymer, and any combination of these. In some embodiments, the step of preparing comprises selecting a precursor material selected from the group consisting of an organic resin, a hybrid organic-inorganic resin, a metal, a metallic alloy, a ceramic, a polymer, and any combination of these.
- Useful organic resins include, but are not limited to, acrylic-based, thiol-based, polyurethane- based, and epoxy-based resins.
- Useful hybrid organic-inorganic resins include, but are not limited to, siloxanes and metal alkoxide-derived precursors, such as those described in US Patent Publication 2018/0088462, which is hereby incorporated by reference.
- the precursor material further comprises additives.
- Useful additives include, but are not limited to, metal and/or ceramic particles (e.g., nanoparticles), other inorganic and/or organic additives, solutions of inorganic and/or organic materials that either form a single phase with the resin, or suspensions and emulsions forming a secondary phase with the resin, inorganic particles, inorganic fibers, organic binders, polymer powder, metal powder, ceramic powder, metal wires (e.g., micro- or nano- wires), metal salt solution, metal ion solution, and any combinations of these.
- precursors for extrusion techniques may include thermoplastic polymers and low melting point metals, with additives that include inorganic particles, fibers, etc.
- material feed stocks for powder bed-based techniques may include metal, ceramic, and polymer powders.
- precursor for binder jet-based techniques use may include these powders in combination with organic binders.
- precursors for direct energy deposition techniques may include metal powders and metal wires.
- other feedstock/precursor materials for additive manufacturing techniques may include metal and ceramic nanoparticle inks for direct ink writing and electrohydrodynamic printing, metal and polymer sheets for lamination- based processes, metal salt or metal ion solutions for electroplating-based and photoreduction-based methods, precursor gases for focused beam-based methods (FEBID/FIBID), and droplets of molten metal for laser-induced forward transfer and magnetohydrodynamic printing.
- the pyrolysis process is carried out over a temperature range selected from the range of 500 °C to 3000 °C and for a duration selected from the range of 1 hour to 336 hours. In some embodiments, the pyrolysis process is carried out over a temperature range select from the range of 500 °C to 900 °C, optionally 500 to 1300 °C.
- the structure is optionally exposed to vacuum and/or an inert gas, or any atmosphere substantially lacking oxygen and water vapor, during pyrolysis. In some embodiments, the pyrolysis process provides for an isotropic shrinkage of said three- dimensional framework to said structure selected from the range of 15% to 80%.
- the method further comprises applying an external stimulus to said structure to change at least one vibrational frequency band gap of said structure.
- the method does not comprise etching a template.
- the composite material system has a density less than or equal to 1500 kg/m 3 , less than or equal to 1200 kg/m 3 , preferably for some applications less than or equal to 1000 kg/m 3 , more preferably for some applications less than 1000 kg/m 3 , more preferably for some applications less than or equal to 900 kg/m 3 , more preferably for some applications less than or equal to 500 kg/m 3 , more preferably for some applications less than or equal to 300 kg/m 3 , more preferably for some applications less than or equal to 150 kg/m 3 , or still more preferably for some applications less than or equal to 100 kg/m 3 .
- the composite material system has a density selected from the range of 100 kg/m 3 to 1500 kg/m 3 , 100 kg/m 3 to less than 1000 kg/m 3 , or any subrange in between.
- the composite material system or structure is characterized by a Young’s modulus of at least 100 MPa, optionally for some
- the composite material system or structure is characterized by a Young’s modulus selected from the range of 100 MPa to 5 GPa, or any subrange in between.
- the composite material system or structure is characterized by a yield strength of at least 5 MPa, preferably for some applications at least 8 MPa, preferably for some applications at least 1 1 MPa, more preferably for some applications at least 15 MPa, more preferably for some applications at least 25 MPa, still more preferably for some applications at least 60 MPa, or still more preferably for some applications at least 100 MPa.
- the composite material system or structure is characterized by a yield strength selected from the range of 5 MPa to 100 MPa, or any subrange in between.
- the composite material system or structure is characterized by not exhibiting catastrophic failure at strain (e) selected from the range of 0.1 to at least 0.5. In some embodiments of the systems and methods disclosed herein, the composite material system or structure is characterized by flow stress of at least 70 MPa, or optionally selected from the range of 70 to 500 MPa. In some embodiments of the systems and methods disclosed herein, the composite material system or structure is characterized by a flexural strength of at least 10 MPa, preferably for some applications at least 20 MPa, or preferably for some applications selected from the range of 10 MPa to 100 MPa, or any subrange therebetween.
- the composite material system or structure is characterized by a bending modulus of at least 1 GPa, preferably for some applications at least 1.4 GPa, preferably for some applications at least 2 GPa, preferably for some applications at least 3.3 GPa, preferably for some applications at least 3.9 GPa, preferably for some applications at least 5 GPa, or more preferably for some applications selected from the range of 100 MPa to 10 GPa, or any subrange therebetween.
- composite material systems having any one or any combination of embodiments of composite material systems and methods disclosed herein. Also disclosed herein are methods for making material systems having any one or any combination of embodiments of composite material systems and methods disclosed herein.
- FIG. 1 Flowchart of method to fabricate composite materials with continuous arbitrary phases.
- FIGs. 2A-2B Embodiment of a composite material with continuous three- dimensional phases with arbitrary geometries.
- FIG. 2A Changing cross-sections in a single truss element.
- FIG. 2B Non-zero curvature and horizontal truss elements.
- FIG. 3. Embodiment of a composite material with continuous three- dimensional phases of shell or surface geometries, with one or more matrix phases.
- FIG. 4 Embodiment of a modular three-dimensional structural element made a composite material described in the previous embodiments.
- the reinforcing phase does not require a shaping process; the geometry is defined a priori.
- FIGs. 5A-5B Embodiment of a structural element made of a composite material described in the previous embodiments, where the in-plane and through- thickness geometries are functionally graded. The resulting part has continuous three- dimensional phases.
- FIG. 6 Embodiment of a phase microarchitecture where resonators are designed to dissipate vibration and provide damping to the material.
- the resulting part has continuous three-dimensional phases.
- FIGs. 7A-7C Sample embodiment of a composite material with continuous three-dimensional phases with arbitrary geometries, reduced to practice.
- FIG. 7A Structural element fabricated from a precursor resin via DLP 3D printing and corresponding micrograph.
- FIG. 7B Post-pyrolysis carbon three-dimensional continuous reinforcing phase and corresponding micrograph.
- FIG. 7C Composite structural element with continuous three-dimensional phases and epoxy matrix phase.
- FIG. 8 Manufacturing process of continuous reinforcing phase with arbitrary geometry via additive manufacturing.
- FIGs. 9A-9B A schematic of a structure with a three-dimensional geometry, or unit cell thereof, that is a tetrakaidekahedron (FIG. 9A), and a composite material system (FIG. 9B) having the structure of FIG. 9A infiltrated by a matrix phase.
- FIG. 9A tetrakaidekahedron
- FIG. 9B composite material system
- FIGs. 10A-10B Polymeric octet lattices.
- FIG. 10A Micrograph of full lattice suspended on a bed of spring structures.
- FIG. 10B Close-up showing 5 pm octet unit cells.
- FIGs. 11A-11 D Pyrolyzed carbon lattices.
- FIG. 11 A Octet lattice of 26% relative density.
- FIG. 11 B Close-up showing sub-micron unit cells.
- FIG. 11C shows sub-micron unit cells.
- FIG. 11 D Close-up on final tetrakaidecahedron geometry.
- FIG. 12 Impact of a 7 pm S1O2 bead on an octet lattice with 27% relative density. The projectile and the lattice are both highlighted in red in the initial frame, prior to impact. Subsequent frames reveal the projectile rebounding from the lattice, with minor debris being ejected. The impact and rebound velocities were 1060 and 560 m/s, respectively.
- FIGs. 13A-13C PMMA resist coating to better bond the lattice to the substrate.
- FIG. 13A Initial carbon lattice.
- FIG. 13B Carbon lattice with a sub-micron PMMA coating.
- FIG. 13C Post-mortem confocal microscopy image showing the impact site and minor permanent deformation.
- FIGs. 14A-14B Approximation of impact as a planar wave through the lattice material.
- FIG. 14A Diagram depicting a planar wave going through a lattice of thickness xiat and substrate thickness Xs.
- FIG. 14B x-t diagram of the elastic plane wave for a worst-case carbon octet lattice of 60% relative density, showing that the (on-average) 4 ns of impact time are not sufficient for elastic waves to reach the substrate and reflect back to the projectile.
- FIGs. 15A-15D Suspended sample fabrication process.
- FIG. 15A The original Si substrates were patterned and etched to create stilts approximately 50 pm in height.
- FIG. 15B The nanowires that tethered the as-pyrolyzed sampled to the substrate were milled using a FIB.
- FIG. 15C The freed sample was captured by a nano- manipulator.
- FIG. 15D The sample was affixed to the stilts using Pt glue.
- FIG. 16 Suspended sample impact experiment. The same rebounding behavior was observed, without any through-thickness complete penetration or catastrophic sample fracture.
- FIG. 17 Summary of impact experiments. A trend between impact energy, a mv 0 , and restitution coefficient, v r /v o , can be observed. No substantial difference was observed across different architectures, while a decrease in restitution was observed for lower relative density samples. The suspended-sample experiment is shown in yellow, while the PMMA-coated one is shown in blue.
- FIGs. 18A-18F Tetragonal unit cell of interest.
- FIG. 18A Unmodified tetragonal unit cell with elliptical cross-section beams in the horizontal direction and circular beams in the vertical direction, (FIG. 18B) slightly buckled geometry, (FIG. 18C) fully buckled geometry, (FIGs. 18D-18F) top views of the unit cells in FIGs. 18A-18C.
- FIGs. 19A-19D Dispersion relations for the tetragonal unit cells.
- FIG. 19A Unmodified unit cell, (FIG. 19B) slightly buckled unit cell, (FIG. 19C) fully buckled unit cell, (FIG. 19D) irreducible Brillouin zone in reciprocal space. Partial band gaps are shaded in green.
- FIGs. 20A-20B Auxetic unit cell.
- FIG. 20A Unmodified unit cell, (FIG. 20B) unit cell with added resonator.
- FIGs. 21 A-21 B Dispersion relations of auxetic unit cells.
- FIG. 21 A Dispersion relations of auxetic unit cells.
- FIG. 21 B unit cell with resonator showing the appearance of a band gap.
- FIGs. 22A-22C Custom ultrasonics setup.
- FIG. 22A Image of the
- FIG. 22B picture of the vacuum chamber and the placement of the transducers
- FIG. 22C CCD image of the setup in vacuum, with a rubber puck between the transducers for validation purposes.
- FIGs. 23A-23E Frequency sweep experiment.
- FIG. 23A Unmodified unit cell, (FIG. 23B) unit cell with resonators, (FIG. 23C) frequency sweep transmitted signal amplitude, (FIG. 23D) close up on sample with no contact, (FIG. 23E) close up on slightly strained sample due to transducer contact. A band gap centered at ⁇ 2.4 MHz was found, and is highlighted in grey.
- FIGs. 24A-24C Chirp transmission experiment.
- FIG. 24A Input chirp signal containing 1-3 MHz
- FIG. 24B FFT on the transmitted signal through a rubber puck, confirming the frequency content of the chirp
- FIG. 24C FFT of the transmitted signal through the resonator-containing sample, showing the same band gap as in the sweep experiment, centered at ⁇ 2.4 MHz.
- FIGs. 25A-25D Elastic surfaces of some sample microstructures.
- FIG. 25A Columnar structure depicting a stiff direction aligned with the z-axis, (FIG. 25B) cubic structure showing preferential directions aligned with the x,y,and z-axes, (FIG. 25C) lamellar structure showing a few orders-of-magnitude difference in stiffness along the x- y axes and the z-axis, (FIG. 25D) a quasi-isotropic structure.
- FIG. 26 Stiffness scaling as a function of relative density. Spinodal structures have a higher absolute modulus and lower, more desirable, scaling exponent.
- FIGs. 27A-27B Curvature probability distributions.
- FIG. 27A Columnar structure, (FIG. 27B) octet truss with 0.5r and r fillets at nodes, where r is the radius of the tubes. The absolute curvatures for the octet structure are significantly higher than those of the spinodal structure.
- FIGs. 28A-28C Shell-based spinodal structure at the nano/microscale.
- FIG. 28A Polymeric structure fabricated via two-photon lithog-raphy, (FIG. 28B) coated structure after FIB milling, exposing the polymer again, (FIG. 28C) resulting shell-based spinodal structure after etching the inner polymer.
- FIGs. 29A-29D Shell-based spinodal structure at the macroscale.
- FIG. 29A Polymeric columnar spinodal structure, (FIG. 29B) top view, (FIG. 29C) resulting carbon reinforcing phase, (FIG. 29D) top view.
- FIGs. 30A-30C Architected plate for blast impact testing.
- FIG. 30A Architected plate for blast impact testing.
- FIG. 30B Polymeric precursor plate and resulting pyrolyzed plate
- FIG. 30C micrograph of a tetrakaidecahedron architecture.
- FIGs. 31A-31 F Cubes of example reinforcing phases.
- FIG. 31 A Polymeric octet cube, (FIG. 31 B) pyrolyzed carbon octet cube from FIG. 31 A, (FIG. 31 C)
- FIGs. 31 D-31 F pyrolyzed carbon 3D kagome beam
- FIGs. 32A-32F Tubular architected component.
- FIG. 32A Polymeric tube with tetrakaidecahedron architecture, (FIG. 32B) top view of FIG. 32A, (FIG. 32C) close up of FIG. 32B, (FIG. 32D) pyrolyzed carbon tube with tetrakaidecahedron architecture prior to infiltration, (FIGs. 32E-32F) close-ups of FIG. 32D.
- FIGs. 33A-33H Fabrication and microstructural characterization of the pyrolytic carbon micropillars.
- FIG. 33A Schematic illustration of the fabrication process. This process includes the TPL DLW of cylindrical pillars from IP-Dip polymer resin and subsequent pyrolysis under vacuum at 900 °C.
- FIGs. 33B-33C SEM images of a representative micropillar before and after pyrolysis, showing substantial volumetric shrinkage.
- FIG. 33D Bright-field TEM image of the pyrolytic carbon. The diffraction pattern in the inset reveals its amorphous microstructure.
- FIGs. 33E-33F HRTEM images of the two regions outlined by solid boxes in FIG. 33D. These images reveal the presence of some sub-nanometer-sized voids (denoted by red arrows).
- FIG. 33G Schematic illustration of the fabrication process. This process includes the TPL DLW of cylindrical pillars from IP-Dip polymer resin and subsequent pyrolysis under vacuum at
- FIG. 33H Raman spectrum of a pyrolytic carbon micropillar.
- the typical G and D bands at the energies 1359 cm 1 and 1595 cm 1 indicate sp 2 -hybridization.
- FIG. 33H EELS of the pyrolytic carbon, where the green and purple shaded areas correspond to the 1 s - J? and 1 s-o* peaks of carbon, respectively. Quantitative analysis of the data indicates that the pyrolyzed carbon contains approximately 96.5% sp 2 bonds.
- FIGs. 34A-34F Uniaxial compression and tension experiments on the pyrolytic carbon micropillars.
- FIG. 34A Compressive stress-strain data of pyrolytic carbon pillars with diameters of 4.6-12.7 pm. All of these micropillars deformed elastically up to -20-30% strain and exhibited marginal plastic strain (-8-10%) before failure. The dashed lines indicate the linear slopes.
- FIG. 34B SEM images of a typical pyrolytic carbon micropillar described in FIG. 34A before and after compression, which reveals the occurrence of brittle fracture via multiple fragments.
- FIG. 34C SEM images of a typical pyrolytic carbon micropillar described in FIG. 34A before and after compression, which reveals the occurrence of brittle fracture via multiple fragments.
- the inset shows an SEM image of the micropillar before compression.
- a sequence of snapshots obtained during the in situ deformation is shown above the plot, with numbered frames corresponding to the same-numbered red arrows in the stress- strain curve.
- the SEM images on the right of the stress-strain data show the
- FIG. 34D Tensile stress-strain data of pyrolytic carbon dog-bone- shaped samples with gauge diameters of 0.7-2.0 pm.
- FIG. 34E SEM images of a typical tensile specimen before and after the experiment.
- FIG. 34F Statistical distribution of tensile fracture strengths.
- FIGs. 35A-35B Change in strength with diameter and the ultra-large elastic limit of pyrolytic carbon micropillars.
- FIG. 35A Variation in compressive strength with increasing micropillar diameter.
- the blue dashed line represents the average
- FIG. 35B Twenty-cycle force-displacement curve of a deformable pillar with a diameter of 1.28 pm under a maximum compressive strain of -23%, showing nearly full recovery in every cycle except the first cycle.
- the SEM images depict the pre-deformation and post- deformation pillar from 20 loading cycles.
- FIGs. 36A-36J Atomistic simulations of the uniaxial compression and tension of pyrolytic carbon nanopillars.
- FIG. 36A Atomic configurations and cross-sectional morphology of a simulated sample with a diameter of 20 nm.
- FIGs. 36B-36C Atomic configurations and cross-sectional morphology of a simulated sample with a diameter of 20 nm.
- FIGs. 36D- 36G Snapshots of a deformed pillar at different compressive strains.
- FIGs. 36H-36J Snapshots of a deformed pillar at different tensile strains. The atoms in FIGs. 36D-36J are colored according to the von Mises atomic strain.
- FIGs. 37A-37C Summary of the combined ultra-high strength/specific strength and large deformability of the pyrolytic carbon micropillars.
- FIG. 37A Ashby chart of strength versus density for various structural materials, including our pyrolytic carbon micropillars.
- FIG. 37B Comparison of specific tensile and compressive strengths between our pyrolytic carbon micropillars and other structural materials.
- FIG. 37C Comparison of specific tensile and compressive strengths between our pyrolytic carbon micropillars and other structural materials.
- FIG. 38 Compressive stress-strain curves of simulated nanopillars with diameter of 10 nm and different densities.
- FIG. 39 Plot of Young’s modulus (GPa) versus density (g/cm 3 ) corresponding to materials or structures from relevant art as well as to certain embodiments of the present invention.
- FIGs. 40A-40E Images corresponding to atomistic configurations of nanopillars formed of carbon allotrope materials.
- the nanopillars shown here have diameters of 10 nm and different densities of 1 .0-1.8 g/cm 3 . Presence of sp carbon, sp 2 carbon, and sp 3 carbon is identified.
- FIG. 41 Model for estimation of density and comparison with densities of pyrolytic carbon reported in recent literatures.
- FIG. 42 In situ compression experiment of pyrolytic micropillar without the residual ring.
- (c) a splitting crack nucleated and rapidly propagated under high compressive stress, leading to the catastrophic fracture of the micropillar.
- FIG. 43 Influence of residual carbon rings on compression of pyrolytic carbon micropillars.
- FIG. 44 Bonding structures of pyrolytic carbon pillars used for atomistic simulations.
- the sp 2 bonds are much more ubiquitous than sp and sp 3 bonds.
- the sp bonds are mainly localized at the edges of the curved graphene layers; the sp 3 bonds generally connect neighboring graphene layers to one another or form at the high- energy curved surface of graphene layers.
- FIGs. 45A and 45B Fracture mechanisms of pyrolytic carbon nanopillars under uniaxial tension.
- FIG. 45A Snapshots of stretched nanopillars at strains of 56.3- 60.5%. Nanoscale cavities (indicated by orange arrow) nucleated and grew up during stretching, and then merged with each other, leading to formation of nanoscale cracks.
- FIG. 45B Snapshots of stretched nanopillars at strains of 61.0-61.8%. As the tensile strain increases, nanoscale cracks propagated along a direction normal to tensile direction, resulting in the smooth fracture surface. All atoms in FIG. 45A and FIG. 45B are colored by atomic von Mises strain.
- FIG. 46 Effects of initial flaws on tensile strength of pyrolytic carbon pillars.
- Panels (a) and (b) Atomic configurations of simulated samples containing initial cracks with length of 4 nm and 8 nm, respectively. All initial cracks are shown by the white flakes.
- Panels (c) and (d) A sequence of snapshots of pillars with initial cracks with length of 4 nm and 8 nm, respectively. The failure of both nanopillars always initiated from the growth and extension of pre-existing nanocracks. Both samples after failure have the smooth fracture surface, showing a brittle fracture mode. All atoms in Panel (c) and Panel (d) are colored by atomic von Mises strain.
- FIG. 47 Summary plot of strength versus fracture strain for our pyrolytic carbon micropillars and other structural materials.
- FIGs. 48A-48F Fabrication and micro structural characterization of pyrolytic carbon nanolattices.
- FIG. 48F An HRTEM image of pyrolytic carbon extracted from the nanolattice, which indicates the amorphous nature of the pyrolytic carbon.
- FIGs. 49A-49F In situ uniaxial compression experiments on pyrolytic carbon nanolattices.
- FIGs. 49A-49B Mechanical response of pyrolytic carbon octet- and iso- truss nanolattices with different relative densities obtained from in situ compressions.
- FIGs. 50A-50B Mechanical properties versus density maps of pyrolytic carbon nanolattices.
- FIG. 50A Young’s modulus and (FIG. 50B) compressive strength of pyrolytic carbon nanolattices plotted versus density on a log-log scale.
- these charts include several micro- and nano-architected materials reported so far, such as alumina hollow nanolattices (1 1 ), alumina-polymer nanolattices (16), glassy carbon nanolattices (18), carbon aerogel (22), graphene aerogel microlattices (23), vitreous carbon nanolattice (24), cellular carbon microstructure (25) and SiOC microlattices (26).
- FIGs. 51A-51 F Mechanical properties versus density maps of pyrolytic carbon nanolattices.
- FIG. 50A Young’s modulus and (FIG. 50B) compressive strength of pyrolytic carbon nanolattices plotted versus density on a log-log scale.
- these charts include several micro- and nano-architected
- FIGs. 51A-51 C Simulated configurations of octet-, iso- and tetrahedron-truss nanolattices with pre-existing defects introduced by imposing the initial deflection of struts.
- the insets show the zoom-in views of local structures with initial deflection of struts.
- FIGs. 51 D-51 F Compressive stress- strain curves of octet-truss, iso-truss and tetrahedron-truss nanolattices with different relative densities and initial specific deflection.
- FIG. 52 Comparison of the specific strength between our pyrolytic carbon nanolattices and other micro- and nanolattices reported so far.
- FIGs. 53A-53H In situ compression tests on polymer nanolattices.
- FIGs. 53B- 53D SEM snapshots of deformed octet-truss nanolattice under different compressive strains.
- FIGs. 53F-53H SEM snapshots of deformed iso-truss nanolattice under different compressive strains.
- the circled regions in FIG. 53C and FIG. 53G indicate the buckling of struts during compression.
- FIGs. 54A-54B Young’s modulus and compressive strength versus density of pyrolytic carbon nanolattices. Young’s modulus and strength versus relative density of octet- and iso-truss pyrolytic carbon nanolattices on log-log scale. Scaling power law slopes are indicated for each architecture. Error bars represent the standard deviations from the average over some data of samples with comparable densities.
- FIG. 55 Relative reduction in strength of nanolattice with initial deflection as a function of the extent of initial deflection.
- FIGs. 56A-56B Comparison between finite-element modelling and
- FIGs. 57A-57D Microstructure characterization of 3D architected carbon structure.
- FIG. 57A SEM image of cross-section and energy dispersive spectroscopy (EDS) spectrum on the cross-section.
- FIG. 57B Raman spectrum with experimental data ( ⁇ ), fitted curves for each band (dot lines), and linear combination of these peaks (red line).
- FIG. 57C X-ray diffraction (XRD) pattern.
- FIG. 57D Transmitted electron microscope (TEM) high resolution image and diffraction pattern (inlet). Scale bars are 5 pm for FIG. 57A, and 5 nm in FIG. 57D.
- FIG. 58A Line analysis of EDS on the cross-section.
- FIG. 58B Particles crushed from the 3D architected carbon structure used for XRD analysis.
- FIG. 59A Representative stress-strain curve for compression.
- Roman numerals corresponds to distinct events shown in FIG. 59B.
- FIG. 59B Photographic images of the compressed 3D architected carbon structure, I at the initial contact, ll-a, b, c at local fractures shown in red doted-circle, III before the second stress release IV at the partial layer collapse shown by red line, V before the third stress release, and VI at the half layer collapse. Substrate and top load cell was grayed out.
- FIG. 60 Stress-strain curve of five samples of the 3D architected carbon structure.
- FIG. 61 A and FIG. 61 B Images showing architected three-dimensional structures having node-free geometries, according to certain embodiments of the invention. Additional exemplary node-free geometries may be found in Abueidda, et al. (“Effective conductivities and elastic moduli of novel foams with triply periodic minimal surfaces”, Mechanics of Materials, vol. 95, April 2016, pages 102-1 15), which is incorporated herein by reference.
- FIGs. 62A-62F Infiltration of reinforcing phases.
- FIG. 62A Shell-based spindodal reinforcing phase, (FIG. 62B) tetrakaidecahedron-tube structure, (FIG. 62C) octet-cube structure, (FIGs. 62D-62F) epoxy-infiltrated composites from the reinforcing phases depicted in FIGs. 62A-62C.
- FIGs. 63A-63D Octet carbon material in compression.
- FIG. 63A Sample prior to compression, (FIG. 63B) failed sample after catastrophic event, (FIG.
- FIG. 64A-64C Octet carbon-epoxy material in compression.
- FIG. 64C stress-strain response of samples.
- FIGs. 65A-65D Four-point bending of carbon octet material.
- FIG. 65A Four-point bending of carbon octet material.
- FIG. 65B Sample prior to experiment, (FIG. 65B) sample after catastrophic fracture event, (FIG. 65C) final sample morphology, (FIG. 65D) resulting stress-strain response,
- FIGs. 66A-66D Four-point bending of epoxy-infiltrated carbon octet materials.
- FIG. 66A Sample prior to experiment, (FIG. 66B) sample at highest bending load, (FIG. 66C) sample morphology after unload showing no visible damage, (FIG. 66D) resulting stress-strain response, corresponding to the outermost edge of the material.
- the term“monolithic” refers to a system, structure, geometry, or other element that is a unitary interconnected and continuous element.
- a monolithic element is formed or composed of a material without joints or seams.
- the term“interconnected” refers to a system, structure, geometry, or other element of which every first portion or first feature is either (i) directly connected to a second portion or second feature of the system, structure, geometry, or other element, or (ii) indirectly connected to a second portion or second feature of the system, structure, geometry, or other element via a third portion or third feature of the system, structure, geometry, or other element.
- no portion or feature of an interconnected system, structure, geometry, or other element is fully isolated from the rest of the system, structure, geometry, or other element.
- the term “continuous” refers to a system, structure, geometry, or other element of which every first portion or first feature is directly or indirectly bonded to, fused with, or otherwise belongs to the same uninterrupted phase with respect to a second portion or second feature of system, structure, geometry, or other element.
- two features which are connected merely by superficial contact (e.g., touching) but are otherwise isolated with respect to each other are not continuous.
- two distinct features, such as fibers or particles, which are merely touching or are woven together may be interconnected but are not continuous with respect to each other.
- a structure or geometry consisting of a plurality of features, such as fibers or particles, each of which is merely touching or woven together with another feature, such as a fiber or particle, may be an interconnected structure or geometry but is not a continuous structure or geometry.
- the term“deterministic” refers a system, structure, geometry, or other element characterized by at least one feature and/or at least one property (e.g., vibrational frequency band gap) that is known and/or controlled to be within 20%, preferably within 10%, more preferably within 5%, more preferably within 1 %, or more preferably within 0.1 % of a determined or desired value.
- a property e.g., vibrational frequency band gap
- deterministic geometry is characterized one or more features each independently having at least one physical dimension which, prior to or during formation of said structure, is pre-determined to be within 20%, preferably within 10%, more preferably within 5%, more preferably within 1 %, or more preferably within 0.1 % of a determined or desired value.
- a deterministic architected three-dimensional geometry of a structure comprises a plurality of features, such as trusses, having one or more physical dimensions (e.g., width, thickness, diameter, length) the values of which are within 20%, preferably within 10%, more preferably within 5%, more preferably within 1 %, or still more preferably within 0.1 % of the value(s) of the one or more physical dimensions designed, such as via a CAD technique, or determined prior to formation of the structure.
- Stochastic geometries or structures, such as random or natural foams, are not deterministic.
- the term“architected” refers to a system, structure, geometry, or feature having features that are designed and formed according to the design.
- an architected structure is deterministic or formed according to
- substantially all features, and physical dimensions thereof are designed, or pre-determined, and formed according to the design such that the substantially all features, and physical dimensions thereof, are substantially equivalent to those of the design.
- a structure has a three dimensional geometry when a three-coordinate system of physical space is required to fully describe the physical dimensions of a unit cell of the structure.
- a three dimensional geometry may be nano-architected and/or micro-architected.
- a structure characterized by a nano-architected three dimensional geometry is a structure characterized one or more features having at least one physical size dimension (e.g., length, width, diameter, or height) the value of which is in the range of approximately 1 nm to less than 1 pm.
- a structure characterized by a nano-architected three dimensional geometry is a structure characterized by a unit cell having whose at least one physical size dimension (e.g., length, width, or height) the value of which is in the range of approximately 1 nm to less than 1 pm.
- a structure characterized by a micro-architected three dimensional geometry is a structure characterized one or more features having at least one physical size dimension (e.g., length, width, or height) the value of which is in the range of approximately 1 pm to 1000 pm.
- a structure characterized by a micro-architected three dimensional geometry is a structure characterized by a unit cell having at least one physical size dimension (e.g., length, width, or height) the value of which is in the range of approximately 1 pm to 1000 pm.
- a“feature” of a system such as a composite material system according to an embodiment, structure, or geometry, such as a three-dimensional geometry according to an embodiment, refers to an element such as, but not limited to, a beam, a strut, a tie, a truss, a sheet, a shell, a sphere, an ellipse, a node, or a combination of these.
- a fillet, a bevel, a chamfer, or similar attribute is a portion of a feature but is not a feature itself.
- a fillet, or rounding of an interior or exterior corner is a portion of one or more features but is not a“feature”, as used herein, itself.
- a fillet between a first truss and a second truss is a portion of the first truss, of the second truss, or a portion of each of the first and second trusses, but the fillet is not itself a“feature”, as used herein, of the three-dimensional geometry or structure.
- A“longitudinal feature” refers to an element whose length (or, size along its longitudinal axis) is at least 50% greater than each of its other
- exemplary longitudinal feature may include, but are not limited to, beams, struts, ties, and trusses.
- a surface feature is a feature that may be better characterized as a flat and/or curved planar feature than a longitudinal feature.
- a surface feature corresponds to a feature that may be approximated or characterized as a mathematical two-dimensional manifold, having a uniform or non-uniform thickness.
- a surface feature corresponds to a feature that may be approximated or characterized as a mathematical two-dimensional manifold, having a uniform or non- uniform thickness, and is an open surface.
- Exemplary surface features include, but are not limited to, sheets and shells.
- A“matrix phase” refers to a material, or a combination of materials, that may at least partially infiltrate a structure of a composite material system.
- a matrix phase may be uniform or non-uniform.
- a matrix phase may be homogeneous or non- homogeneous.
- At least partial infiltration of the structure refers to at least partial filling of void space of a structure.
- at least partial infiltration of the structure refers to at least partial filling of accessible void space of a structure.
- Non-accessible void space of a structure may refer to closed void regions (e.g., hollow truss or hollow portion of a spinodal geometry) into a matrix phase may not penetrate without first etching or performing another destructive process on said structure.
- the matrix phase is not a coating, such as a coating deposited via ALD, sputtering, or electrophoretic deposition.
- the matrix phase is not an electrolyte, such as an electrolyte of an electrochemical cell, including solid-state electrolytes.
- A“vibrational frequency band gap” refers to a frequency, or frequency range, corresponding to vibration (or, oscillation) of a structure, composite material system, or structure thereof, where the magnitude or energy of oscillation(s) at said frequency, or said frequency range, is at least 10 times (one order-of-magnitude), at least 20 times, at least 50 times, preferably at least 100 times (two orders-of-magnitude), preferably for some applications at least 200 times, or still more preferably for some applications at least 500 times, less than the magnitude or energy of oscillations at frequencies outside of the“vibrational frequency band gap.”
- a vibrational frequency band gap may be characterized by a midpoint frequency and/or a frequency width.
- a partial vibrational frequency band gap is a vibrational frequency band gap existing along one or more directions (e.g., X, Y, Z, or any direction or vector in between), but not existing along all directions.
- a complete vibrational frequency band gap is a vibrational frequency band gap existing along all directions (e.g., X, Y, Z, or any direction or vector in between).
- cross-sectional physical dimension refers to a physical dimension of a feature measured in a transverse or cross-sectional axis.
- the transverse axis is perpendicular to a longitudinal axis of the feature.
- a cross-sectional physical dimension corresponds to a width or a diameter of a feature such as a beam, strut, or tie.
- a longitudinal physical dimension is a dimension of a feature along the longitudinal axis of the feature, wherein the longitudinal axis is perpendicular to a cross-sectional axis.
- the longitudinal physical dimension is measured between two nodes.
- the longitudinal physical dimensions is measured between to physical ends of a structure.
- unit cell refers to the smallest arrangement, configuration, or geometry of a plurality of features such that an entire structure, or three-dimensional geometry thereof, characterized by said unit cell can be formed by repetition of said unit cell.
- repetition of the unit cell in three dimensions may form a three- dimensional structure.
- the entire structure may be a three-dimensional structure, such as a three-dimensional porous structure.
- Young’s modulus is a mechanical property of a material, device or layer which refers to the ratio of stress to strain for a given substance. Young’s modulus may be provided by the expression:
- E Young’s modulus
- AL the length change under the applied stress
- F the force applied
- A the area over which the force is applied.
- Young’s modulus may also be expressed in terms of Lame constants via the equation: m( l + 2m)
- l and m are Lame constants.
- the Young’s modulus may be measured according a method conventionally known, or not yet known, in the art.
- the Young’s modulus corresponds to the slope of a linear portion of a stress-strain curve as described by Roylance (“Stress-Strain Curves,” MIT course, August 23, 2001 ; accessed at time of filing at http://web.mit.edU/course/3/3.1 1 /www/moduies/ss.pdf).
- an average density of a structure is the arithmetic mean of at least two measurements performed identically, of the density of said structure.
- the term“density” refers to volumetric mass density. Density is represented in units of mass-per-volume (e.g., g/cm 3 ). When referring to a material, the term density corresponds to the volumetric mass density of the material. When referring to a structure, the term density corresponds to the volumetric mass density of the structure, which is a function of the geometric configuration (geometry) of the structure as well as a function of the material(s) of which the structure is formed, such that an increase in porosity of said structure corresponds to a decrease in density of said structure.
- the density of a structure may be measured according a method conventionally known, or not yet known, in the art.
- the density of a structure may be determined by determining mass, height, and diameter for a disk- shape sample, and then calculating the determined mass divided by volume for the sample, with assuming the sample is substantially a complete circle.
- relative density refers to a volume fraction of solid material in a composite material system, structure, or feature.
- a relative density corresponds to a ratio of density of a structure to density solid material (or the combination of materials), of which the structure is composed.
- Relative density may be represented as a fraction (the ratio of densities) or as a percentage (the ratio of densities x 100%).
- relative density of a structure, or a three- dimensional geometry thereof, before pyrolysis is substantially the same to that after pyrolysis.
- the term“specific strength” refers to a ratio of strength to density of a material, system, structure, or feature where strength refers to force per unit area at the point of failure of the material, element, or structure. Specific strength may also be referred to as strength-to-weight ratio. In an embodiment,“strength” refers to
- compressive strength is the maximum stress a material can sustain under crush loading.
- compressive strength of a material, structure, or element that fails by shattering fracture can be defined within fairly narrow limits as an independent property.
- the compressive strength of a material, structure, or element that does not shatter in compression is the amount of stress required to distort the material an arbitrary amount.
- compressive strength of a material, structure, system, feature, or element that does not shatter in compression can be calculated as the stress at a 0.2% strain offset from the linear portion in a stress-strain curve.
- compressive strength is calculated by dividing the maximum load, on the material, structure, or element, by the original cross-sectional area of the material, structure, or element being examined.
- the term“stiffness” refers to an extent to which a material, structure, system, or feature resists deformation in response to an applied force. Stiffness corresponds to a ratio of force applied to a material, structure, or element versus the displacement produced by the applied force along the same degree of freedom (e.g., same axis or direction) exhibited by the material, structure, or element.
- the term“specific stiffness” refers to a ratio of stiffness to density of the material, element, or structure. In an embodiment, the stiffness of a material, structure, or element is the Young’s modulus of the material, structure, or element.
- a structure has a node-free geometry (i.e. , free of node features).
- the node-free geometry has exceptional mechanical resilience. Mechanical resilience may be understood, for example, in terms of strain-to-failure and strength-to-failure.
- strength-to-failure of a material, element, or structure corresponds to compressive strength of the material, element, or structure.
- a structure of the invention has a strain-to-failure of 2% to 5%, optionally 2.9% to 3.5%.
- Strain-to-failure may be determined according a method conventionally known, or not yet known, in the art. For example, strain-to-failure may be determined from the strain value corresponding a linear portion, such as the third linear portion, of stress vs. strain data until sudden stress loss (fracture) of a structure.
- additive manufacture refers to a process for forming a structure or feature via deposition, or otherwise building up, of a material.
- the terms“additive manufacture process” and“additive manufacturing process” may be used interchangeably.
- An additive manufacture process may involve layer-by-layer deposition of a material to form a complex three-dimensional structure or element.
- the deposited material may include, but is not limited to, inorganic materials, hybrid organic-inorganic materials, polymers, metals, or combinations of these.
- Exemplary additive manufacture processes include, but are not limited to, 3D printing, stereolithography (SLA), fused deposit modeling (FDM), and 2-photon lithography.
- an additive manufacture process does not require a subtractive manufacture to form the structure or element.
- subtractive manufacture processes include, but are not limited to, milling, machining, electron discharge machining, carving, shaping, grinding, drilling, and etching.
- an additive manufacture process involves or is aided by computer-aided design (CAD).
- CAD computer-aided design
- the term“defect” may refers to a fabrication-induced imperfection, or unintended feature or property, such as, but not limited to, local deformation, crack, beam junction offset, beam bulging, curvature of a strut, and pit or void.
- node may refer to a junction or intersection of a plurality of features, such as beams or struts.
- a structure may have a three-dimensional geometry that is a node-free geometry.
- the core of a feature corresponds to the feature’s internal volume excluding that of any coatings, particularly coatings introduced after a pyrolysis process, present thereon.
- prepolymer refers to a monomer or mixture comprising one or more monomers where the monomer(s) have been reacted to an intermediate molecular mass state.
- the prepolymer is capable of undergoing further polymerization to a fully cured higher molecular weight state.
- prepolymer and monomer may be used interchangeably.
- polymer refers to a molecule composed of repeating structural units connected by covalent chemical bonds often characterized by a substantial number of repeating units (e.g., equal to or greater than 3 repeating units, optionally, in some embodiments equal to or greater than 10 repeating units, in some embodiments greater or equal to 30 repeating units) and a high molecular weight (e.g. greater than or equal to 10,000 Da, in some embodiments greater than or equal to 50,000 Da or greater than or equal to 100,000 Da).
- Polymers are commonly the polymerization product of one or more monomer precursors.
- the term polymer includes homopolymers, or polymers consisting essentially of a single repeating monomer subunit.
- polymer also includes copolymers which are formed when two or more different types of monomers are linked in the same polymer.
- Copolymers may comprise two or more monomer subunits, and include random, block, brush, brush block, alternating, segmented, grafted, tapered and other architectures.
- Useful polymers include organic polymers or inorganic polymers that may be in amorphous, semi-amorphous, crystalline or semi-crystalline states.
- Polymer side chains capable of cross linking polymers (e.g., physical cross linking) may be useful for some applications.
- the term“substantially” refers to a property that is within 10%, within 5%, within 1 %, or is equivalent to a reference property.
- a ratio is substantially equal to 1 if it the value of the ratio is within 10%, optionally within 5%, optionally within 1 %, or optionally equal to 1 .
- a composition or compound of the invention such as an alloy or precursor to an alloy, is isolated or substantially purified.
- an isolated or purified compound is at least partially isolated or substantially purified as would be understood in the art.
- a substantially purified composition, compound or formulation of the invention has a chemical purity of 95%, optionally for some applications 99%, optionally for some applications 99.9%, optionally for some applications 99.99%, and optionally for some applications 99.999% pure.
- the term“mitigated energy” or“energy mitigated” refers to the energy that is redirected from a composite system, structure, feature, or material and does not cause failure of the composite system, structure, feature, or material (e.g., the energy of a particle before impact plus the energy of the particle after only if the velocity vector is different than the initial one).
- the term“impact energy” refers to energy of an impactor before impact.
- the term “energy absorbed” or“absorbed energy” refers to a difference between the impact energy and the rebound energy of an impactor (e.g., a particle).
- a composite material system has at least one monolithic structure (or,“reinforcing phase”) with a three-dimensional geometry where the centerline of a truss element does not extend from an edge through the entirety of the material (as opposed to a waveguide process), but instead can initiate and terminate at arbitrary points within the material.
- the centerline of truss elements can be placed in any orientation within the material— including perpendicular to the thickness direction— as opposed to waveguide processes where this is not possible.
- a given truss element can have arbitrary cross-section, which can also change throughout the truss element.
- the centerline of a given truss element is allowed to have non-zero curvature.
- One or more matrix phases fill the volume around the reinforcing phase(s).
- the phases can be composed of different material classes, including but not limited to, polymer, ceramic, carbon, and metal.
- the composite material system has a continuous reinforcing phase with a three-dimensional shell or surface geometry, with negative, zero, or positive Gaussian curvature.
- the walls or membranes of the shell geometry can have varying thickness throughout the material.
- the surface geometry can conform enclosed cavities that are separated from an external matrix phase.
- One or more matrix phases fill the volume around the reinforcing phase(s).
- the phases can be composed of different material classes, including but not limited to, polymer, ceramic, carbon, and metal.
- a modular three-dimensional structural element of an arbitrary shape is made of the composite material described in previous embodiments.
- the reinforcing phase of the material will have the geometry of the ultimate structural component, as a continuous phase.
- the topology of the structural element can have zero or multiple holes (i.e. , monolithic composite component or tubular component, respectively). The resulting holes can be infiltrated with a different matrix phase or left unaltered.
- a structural component of an arbitrary shape is made of the composite material described in previous embodiments, with functionally graded geometry of one or more of the phases.
- the continuous lattice architectures or surfaces of the reinforcing phase(s) can change through-thickness and in-plane, while remaining continuous.
- the cross-sections and thicknesses can also change without affecting the continuity of the phases.
- the micro structure of the continuous reinforcing phase of the composite material presented in previous embodiments can have features that serve as resonators and provide damping to the material.
- the resonators could be surrounded by or isolated by a matrix phase.
- a method of making a three-dimensional composite material system with arbitrary architecture may include designing an arbitrary architecture (which can be periodic) through Computer Aided Design (CAD) tools, selecting a desired precursor resin, and exposing the resin to the desired layer-by-layer pattern characteristic of additive manufacturing technologies including but not limited to SLA and DLP.
- CAD Computer Aided Design
- additional resin is then removed and the sample is post-cured with UV and heat treatments, followed by a pyrolysis process with specified temperature profile and in a controlled environment.
- the structure is then infiltrated with one or more materials, aided by vacuum and sonication processes, ultimately forming the composite material with continuous and arbitrarily shaped phases.
- the composite material systems disclosed herein provide an improvement from typical carbon fiber composite materials in that the weak interlaminar interfaces are eliminated, resulting in superior material response under bending and compression. Having fully interconnected reinforcing phases may also provide benefits for impact absorption applications, in which the in-plane properties of a thin material can determine the degree of damage. Additionally, the method presented above provides a clear advantage in manufacturing structural components by avoiding any shaping processes but instead fabricating the reinforcing phase in the final desired geometry.
- the fabrication process embodied by FIG. 1 begins with the design of one or more geometries that will serve as the reinforcing phase of the composite material.
- the precursor resin may determine the constitutive properties of the resulting reinforcing phase, while the architecture will determine the structural response (i.e., stretching or bending dominated).
- the structure is fabricated using additive manufacturing
- the printed structure may then be placed in a furnace to undergo a pyrolysis process in vacuum or inert atmospheres.
- the resulting reinforcing phase can be a carbon or ceramic material.
- An optional coating process could be done prior to infiltrating the resulting reinforcing phase with a selected matrix phase.
- additional processes such as vacuum degassing or sonicating can help ensure complete infiltration of the matrix phase.
- the resulting composite can be post-cured through UV or heating processes.
- a subset of a carbon reinforcing phase 10 made through the process described above is embedded in an epoxy matrix 16.
- a stretching-dominated architecture was chosen due to its high stiffness-to-density ratio— unattainable by the bending-dominated architectures achievable via polymer waveguide patterns.
- a given truss element in this structure also has a variable cross-section, reinforcing the lattice nodes 12 and increasing the stiffness compared to a constant cross-section structure.
- truss elements 14 can initiate and terminate at any point within the material, not necessarily at an edge, as required by waveguide processes.
- FIG. 2B A modification of this embodiment is shown in FIG. 2B, where a given truss element is allowed to have non-zero curvature 18, and truss elements can be oriented perpendicular to the thickness direction 20.
- FIG. 3 An embodiment presented in FIG. 3 shows a subset of a continuous 3D carbon phase made of shells or surfaces 22, which is infiltrated by an epoxy matrix phase 26.
- the surfaces in the reinforcing phase can have a non-zero Gaussian curvature, which cannot be attained through waveguide processes.
- This geometry was achieved by using the surfaces of an octet-truss structure. In this geometry, isolated regions 28 can be fabricated to prevent infiltration from the matrix phase 26, constituting a gaseous phase.
- the thickness of the surfaces in this structure are designed to be non-constant 24, which is not possible through waveguide processes.
- FIG. 4 Another embodiment, presented in FIG. 4, shows a modular structural element made of a composite material as described in previous embodiments.
- the reinforcing phase 30 is designed to have the same shape as the structural component (e.g., a tube), requiring no additional shaping processes. In this case, a bending-dominated architecture was chosen to add compliance and increase the energy absorption capability of the part.
- the structural component has a primary matrix phase 32, while the inner volume of the tube can be left empty or it can be filled with a secondary matrix phase 34.
- FIGs. 5A-5B present an embodiment in which functional grading of a structural component (made from a composite material as described in previous embodiments) is achieved.
- the structural part has one continuous reinforcing phase with several different geometries 36, 40, 42, and 46.
- a bending-dominated structural component made from a composite material as described in previous embodiments.
- tetrakaidecahedron architecture is used for the top region, in which the cross-sectional area of the elliptical truss elements increases from 36 to 40 to 42.
- the domain transition 38 from region 36 to region 40 is continuous, and the connectivity is unaltered (i.e., truss elements do not end abruptly— as is the case with some functional grading attained through waveguide processes).
- the bottom region 46 consists of a stretching- dominated octet-truss architecture with circular cross-section truss elements and continuous transition 44 to the top region.
- a stiff and damping composite material is made through the design of resonators in the micro structure of the phases, as shown in FIG. 6.
- the unit cell 48 is made of an octet-truss architecture with a resonator 50 inside the unit cell.
- the resonator consists of a cantilever beam with added micro-inertia at the free end, which is tuned to resonate at a given frequency w, determined by the length of the beam and the amount of micro-inertia at the free end.
- the unit cell can be made with a combination of truss elements and shells, which can isolate the resonator from the primary matrix that infiltrates the reinforcing unit cell 48. If shells are present, the inner volume of the octahedron within the octet 52 can be left empty to allow free vibration of the resonator, allowing damping properties in an otherwise stiff material.
- FIGs. 7A- 7C An embodiment which has been reduced to practice is depicted in FIGs. 7A- 7C.
- a sheet with a three-dimensional continuous octet-truss architecture 54 of overall dimensions 12.5 4 c 0.13 cm, is fabricated via DLP 3D printing using an Autodesk Ember printer and the PR-48 resin.
- the unit cell size in the resin structure 56 is ⁇ 1.3 mm, with circular cross-section truss elements.
- the resin structure is then pyrolyzed in a furnace in an inert atmosphere at a peak temperature of 1000 ° C.
- the resulting carbon structure 58 undergoes isotropic shrinkage to 40% of the original volume, with only 7% of the original mass.
- the resulting carbon unit cells 60 maintain the original octet-truss geometry and a characteristic size of ⁇ 500 pm.
- the carbon structure is then infiltrated by an epoxy matrix phase 62, becoming the reinforcing phase 64 of the composite structural sheet.
- FIG. 8 depicts one possible method of manufacturing the reinforcing phase of the composite material described in previous embodiments via DLP or SLA 3D printing.
- a printer head 66 is bonded to the edge of the reinforcing phase, and pulls the structure vertically during the printing process.
- the print screen 70 has a layer of uncured precursor resin which polymerizes as an arbitrary exposure pattern 72 is projected from below. Note that this allows truss elements 68 with arbitrary cross-sections which commence and terminate away from the edges of the structure, in addition to truss elements which are perpendicular 74 to the build direction.
- Example 1 Impact Response of 3D Carbon Architectures
- a sufficiently large tessellation (approximately 60 c 60 c 15 unit cells) was selected such that the effective sample size was much greater than the size of a unit cell, allowing the lattice to be approximated as an effective material.
- the polymeric samples were then subjected to a pyrolysis process in vacuum up to 900°C, resulting in monolithic carbon lattices with isotropic shrinkage of 80%, while retaining the original geometry (see FIGs. 1 1 A- 1 1 D).
- the resulting carbon unit cells had sub-micron dimensions, with beam diameters down to ⁇ 200 nm. Although minor warping takes place during pyrolysis, the final unit cell geometry corresponds to the original polymeric one.
- the resulting carbon architectures (i.e., the reinforcing phases) were subjected to supersonic impact by accelerating S1O2 particles with diameters ranging from 7 to 14 pm. In all cases the particle diameter was at least one order-of-magnitude larger than the characteristic unit cell size.
- the method employed is defined as laser induced particle impact test (LI PIT) (8; 9), which enables controllable impact velocities of up to 1 km/s while capturing the impact process with high-speed cameras.
- FIG. 12 shows a characteristic experiment for an octet lattice with 26% relative density, and an impact velocity of 1060 m/s.
- the matrix phase may increase energy dissipation or mitigation because the matrix phase corresponds to additional inertia (i.e., mass).
- a viscoelastic matrix such as a polymer may further dampen vibrations or impact energy.
- the strength of the material may also increase, since the matrix may serve to prevent cracks from opening/propagating. Specific values of these increases may depend heavily on the choice of architecture and materials.
- a ‘coated sample’ covered by a thin layer of epoxy
- a composite material system having a structure partially infiltrated by a matrix phase (e.g., epoxy).
- adding a thin polymeric layer decreased the restitution coefficient to about 0.65 of that for the uncoated sample (35% reduction). This translates to the particle having 58% less kinetic energy upon rebound.
- the energy mitigation measure does not change since the particle still rebounds and structural integrity is maintained, but the energy dissipated/absorbed (i.e.
- inclusion of a matrix may result in a reduction of the restitution coefficient, but an increase in energy absorption. This means less energy will be transferred back to the impactor to travel in the opposite direction, since some of it is absorbed due to the viscoelastic/plastic properties of the matrix.
- Having a matrix may enhance all damping properties compared to the structure free of the matrix phase. For instance, it may increase a vibrational frequency band gap width or even decrease the transmission intensity of vibrations at some frequencies. From a static perspective, the strength of the materials may significantly increase when the matrix phase is present compared to a structure free of the matrix phase, and the failure may go from catastrophic/brittle to ductile-like.
- each unit cell was assumed to have a polymeric core with a Si coating.
- the horizontal beams had a polymer minor radius of 0.25 pm, a major radius of 0.9 pm, and a Si coating of 0.4 pm, while the vertical beams had a polymer radius of 0.9 pm and an identical coating.
- the original tetragonal unit cell had dimensions 20 c 20 c 5 pm.
- FIGs. 19A-19D show the appearance of partial band gaps in the x- and -y directions (due to symmetry), corresponding to frequencies that cannot propagate throughout a material comprised of said unit cells.
- the appearance of band gaps in FIGs. 19B-19C is attributed to Bragg scattering enabled by the buckled geometry.
- the vibrational frequency band gap widths may scale linearly with the characteristic length in the architecture.
- the dispersion relation of the unmodified auxetic unit cell shows no band gaps in the direction of interest, while adding a resonator (see FIG. 21 B) introduces a band gap at 1 .5 MHz.
- the width and location of this band gap is fully tunable based on unit cell dimensions, materials, and resonator parameters.
- FIGs. 25A-25D show unparalleled elastic tunability, which cannot be achieved with commonly studied beam-based architectures. Besides this highly tunable behavior, spinodal structures can exhibit Young’s moduli that approach the theoretical bounds and are substantially greater than other structures such as trusses and triply-periodic minimal surfaces (14-16), as shown by numerical simulations on these structures (see FIG. 26).
- FIGs. 30A-30C Architected plate for blast impact testing.
- FIG. 30A Polymeric precursor plate and resulting pyrolyzed plate,
- FIG. 30B micrograph of an octet carbon architecture
- FIG. 30C micrograph of a tetrakaidecahedron architecture.
- Example 5 Reinforcing-phase Blocks of Varying Architectures
- FIGs. 31A-31 F Cubes of example reinforcing phases.
- FIG. 31 A Polymeric octet cube
- FIG. 31 B pyrolyzed carbon octet cube from FIG. 31 A
- FIG. 31 C pyrolyzed carbon 3D kagome beam
- FIGs. 31 D-31 F close-ups of FIGs. 31A-31 C.
- FIGs. 32A-32F Tubular architected component.
- FIG. 32A Polymeric tube with tetrakaidecahedron architecture, (FIG. 32B) top view of FIG. 32A, (FIG. 32C) close up of FIG. 32B, (FIG. 32D) pyrolyzed carbon tube with tetrakaidecahedron architecture prior to infiltration, (FIGs. 32E-32F) close-ups of FIG. 32D.
- An area-normalized energy mitigation metric can be defined as where 14/ is the absolute energy mitigated (absorbed and/or redirected) and A is the area associated with the impact.
- Kevlar sheets were perforated by the projectile and lost physical integrity, while the lattice underwent minor permanent deformation and was not perforated by the impactor.
- Example 8 Carbon by design through atomic-level architecture
- Metallic and ceramic materials generally have densities beyond 2.7 g/cm 3 .
- Polymers 2 and porous materials are lightweight, and their densities are much lower than those of most metals and ceramics. These materials are significantly deformable and can typically sustain elastic strains beyond 50% 2-5 , but their strengths are only on the order of -10 MPa.
- Single crystalline metals with extrinsic dimensions i.e., sample size below -10 pm exhibit the so-called“smaller and stronger” size effect 9-11 ; examples include Au nanowires/nanopillars with diameters of tens of nanometers that exhibit ultra-high tensile strengths of 5.6 GPa, close to the theoretical limits 10 . This ultra-high strength is associated with a pristine and nearly defect-free crystalline microstructure and/or dislocation source exhaustion 9 at nanoscale.
- micro-sized shape memory zirconia pillars with few crystal grains along the gauge section can withstand pseudo- elastic strains of approximately 7% by undergoing a martensitic phase transformation; the compressive strengths of these ceramic pillars were up to 1 .5-2.5 GPa.
- the resultant polymer-based composite typically have strengths up to ⁇ 0.5 GPa 13 ’ 14 .
- Carbon-family materials contain a large number of allotropes 15 due to the unique electronic structure of the carbon atom, which allows the formation of sp-, sp 2 - and sp 3 -hybridized bonds.
- the mechanical and physical properties of carbon materials can vary widely as a result of different bonding structures.
- graphene and carbon nanotubes with 100% sp 2 bonds have been reported to have ultra-high tensile strengths up to 100 GPa 16 .
- the mechanical properties of these two allotropes are extremely sensitive to defects such as vacancies, pentagon-heptagon pairs, and grain boundaries, which can significantly decrease their strength due to stress concentrations around the defects 16 20 .
- Bulk pyrolytic carbon samples 26 prepared at 1000 °C had an optimal hardness of 4 GPa and a density of 1.1 -1 .4 g/cm 3 .
- Micro-sized glassy carbon 27 synthesized at a high temperature of 400-1000 °C and a high pressure of I Q- 25 GPa exhibited a compressive strength of 9 GPa and a density of 2.0-2.5 g/cm 3 .
- the pyrolytic carbon materials usually have a cleavage plane with a fracture strain below 3% 27 .
- Glassy carbon nanolattices 28 ’ 29 with characteristic strut sizes of approximately 200 nm and densities of 0.3-0.7 g/cm 3 have been fabricated via pyrolysis using photoresist- based microarchitectures made via two-photon lithography, achieving a compressive strength of approximately 300 MPa at a fracture strain below 10%.
- the microstructures of these pyrolytic carbon materials typically consist of curved carbon layers or fullerene- like fragments with dimensions of a few nanometers, leading to a strong dependence of their mechanical properties and performance on the initial precursors, the atomic-level microstructure after pyrolysis, and processing temperature and pressure 25 ⁇ 26 .
- micropillars comprise 1 nm-sized curled graphene fragments, an atomic-level architecture achieved by controlling the precursor material and conditions of pyrolysis.
- In situ nanomechanical testing showed that the pyrolytic carbon have ultra-large elastic limits of 20-30%, high tensile and compressive strengths of 2.5 and 1 1 .0 GPa, low densities of 1.0-1.8 g/cm 3 , and ultra-high specific strengths up to 8.07 GPa/g cm 3 , and that samples with diameters below 2.3 pm can undergo substantial plastic deformation without failure even at applied strains in excess of 40%, exhibiting a rubber-like behavior.
- FIG. 33A shows a schematic of the fabrication process of cylindrical micropillars with diameters of 6-50 pm and heights of 12-100 pm, printed using two- photon lithography direct laser writing (TPL DLW) from IP-Dip, a commercial acrylate- based photoresist.
- TPL DLW two- photon lithography direct laser writing
- a residual carbon ring visible on the silicon substrate represents the footprint of the original pillar and the constraint posed by the substrate during pyrolysis.
- FIG. 33D contains a representative high-resolution TEM (HRTEM) image of the pyrolytic carbon pillar, with the selected area electron diffraction (SAED) pattern in the inset, revealing its amorphous microstructure.
- HRTEM high-resolution TEM
- SAED selected area electron diffraction
- FIGs. 33E-33F indicate the presence of numerous 1.0-1 .5 nm-sized curled atomic fragments, which create sub-nanometer-sized voids (indicated by red arrows in FIGs. 33E-33F), distributed randomly throughout the pillar volume.
- Both the size of the carbon layer fragments and spacing between neighboring layers in our pyrolytic carbon samples are much smaller than those (about 4-6 nm and 1 .67-1.99 nm, respectively) fabricated previously 26 27 .
- These microstructural features provide a useful foundation for estimating the density of pyrolytic carbon micropillars by augmenting a reported geometric model developed for non-graphitized glassy carbon 26 . In this geometric model, the density is dependent on the average size and curvature of the carbon layer and on the spacing between neighboring layers. Using this model, we determined the density of the pyrolytic carbon micropillars in this work to be 1.0-1.8 g/cm 3 , which is close to that of low-density type-l glassy carbon 27 30 .
- FIG. 33G shows the Raman spectrum of a representative pyrolytic carbon micropillar, which contains two prominent peaks at Raman shifts of 1359 cm -1 and 1595 cm -1 that correspond to the graphitic D and G peaks, respectively.
- the ratio (ID/IG) of the integrated area under the D band to that under the G band allowed us to calculate the approximately characteristic crystallite size L of the curled carbon layer fragment 31 observed in the HRTEM images (FIGs. 33E-33F), as indicated by the following equation 31 :
- the characteristic crystallite size of the carbon layer fragment was calculated to be 2.4 nm, which is basically consistent with the size of 1 .0-1 .5 nm determined from our HRTEM
- the fraction of sp 2 bonds was estimated by using the two-window method 32 and adopting all-sp 2 raw glassy carbon as a reference material 27 .
- the fraction of sp 2 bonds is as high as 96.5%, which indicates the dominance of sp 2 hybridization in the pyrolytic carbon micropillars.
- This result is consistent with previous experimental observations that pyrolytic carbon materials treated at high temperature contain mainly disordered sp 2 bonds 27 because sp 3 - hybridized amorphous carbon is unstable above -700 °C 30 . This result also implies that these bonds correspond to layers of graphene. More details on the estimations and analyses based on the Raman spectra and EELS data are supplied in the description of method later in this Example.
- microstructural characterization revealed that our pyrolytic carbon is an assembly of nanometer-sized curled graphene fragments interspersed with sub-nanometer-sized voids. Overall, this specific and delicate microstructure was designed and created by selecting the precursor materials, and controlling the dimensions/geometry of the printed samples and the pyrolysis conditions.
- FIG. 34A shows all compressive stress-strain data sets for micropillars with diameters from 4.6 pm to 12.7 pm. It appears that all the micropillars deformed smoothly until failure, first deforming elastically up to approximately 20-30% strain, then yielding and plastically deforming over an additional -8-10% strain before fracture. Nonlinear behaviors occurred under the first -1-3% strain due to slight misalignment at the top surface of the micropillars.
- Young’s modulus was 16-26 GPa based on fitting the linear elastic portions of the stress-strain curves in FIG. 34A.
- FIG. 34B shows SEM images of a typical micropillar with a diameter of 7.17 pm before and after deformation, demonstrating that it broke into small pieces via brittle facture.
- FIG. 34C shows the compressive stress-strain response of a 2.25 pm-diameter micropillar, which is characterized by a linear elastic regime up to -10% strain, followed by an extensive plateau-like plastic region up to -25% strain, and a final stage in which the stress rapidly increased from 5.48 to 12.63 GPa over a strain increase of -18%.
- This stress-strain curve is similar to that of rubber.
- FIG. 34C depicts a sequence of snapshots of this sample during the experiment, with the numbered frames corresponding to the same numbered red arrows in the data.
- FIG. 34C shows the detailed in situ deformation process of another micropillar with a diameter of 2.26 pm under compression and captures the nucleation and propagation of the splitting microcrack.
- FIG. 42, panel (d) show similar features to the plot in FIG. 34C.
- a clear difference between these two data sets is that a large strain burst is visible in FIG. 42, panel (d), which may be caused by the fast propagation of microcracks.
- a similar deformation and failure signature is observed during the compression of nearly all the 2 pm-diameter micropillars.
- FIB residual carbon ring
- FIG. 43 the compressive deformation of a 1.86-pm-diameter micropillar that retained the residual carbon ring, which bulged and detached from the substrate during compression and led to a substantial strain burst at a strain of -36%, as shown in FIG. 43, panel (d).
- the maximum attained stresses in FIG. 43, panel (d) are comparable to those in FIG. 34C and FIG. 42, panel (d), which suggests a marginal contribution of the residual carbon ring to the strength.
- FIG. 34D summarizes the tensile stress-strain data for samples with diameters of 0.7-2.0 pm. We observed that all the samples failed after linear elastic loading to an elongation of 10- 25% via brittle fracture.
- In situ tension of pyrolytic carbon micropillar with diameter of 1.5 pm is performed. The micropillar is stretched to fail with a smooth fracture surface; the tensile fracture strain is up to about 26%.
- a typical smooth fracture surface is shown in FIG. 34E.
- FIG. 34F A statistical distribution of the tensile strengths of all tested pyrolytic carbon samples is shown in FIG. 34F and fits a two-parameter Weibull distribution,
- FIG. 35A presents all experimental data obtained from the compression experiments, where the strength is defined as the compressive fracture stress.
- This plot reveals that for samples with diameters larger than 2.3 pm, the compressive strength c y increases with decreasing diameter D according to a power law, G y -Cr 0 37 (FIG. 35A).
- This scaling law agrees well with the theoretical prediction of a y ⁇ D ° 40 , which was derived from the asymptotic analysis of a fracture mechanics-based model 34 describing the compressive failure of quasi-brittle columns with characteristic diameter D.
- the columns are found to fail via the propagation of a splitting crack with an initial length h, similar to the experimental observations (e.g., FIG. 34C and FIG. 42).
- This model also offers an expression for the theoretical limit, e strength 34 : 2.76
- the micropillars can sustain an ultra-high compressive stress of 7.2-1 1.3 GPa and a high compressive strain in excess of 40%.
- the significant fluctuations in the compressive strength of the micropillars with D ⁇ 2.3 pm mainly arise from the variation in the length of the initial splitting microcrack h.
- the compressive strengths of the micropillars with D ⁇ 2.3 pm are, on average, higher by a factor of 3.5 than the corresponding tensile strengths of 0.8-2.5 GPa.
- FIG. 35B shows a 20-cycle force-displacement data set of a 1.28 pm-diameter micropillar with a maximum compressive strain of 23%.
- the simulated samples consist of many -1 nm-sized curled graphene layer fragments and possess a density of 1.4 g/cm 3 , which is consistent with the TEM observations of our experimental samples, as illustrated in FIG. 36A. These fragments were connected by covalent bonding or van der Waals interactions.
- the magnified image in FIG. 36A shows that the spacing between neighboring graphene fragments is approximately 0.4 nm and that several sub-nanometer-sized voids are present adjacent to them, as in the HRTEM images in FIGs. 33D-33F.
- the hybridization of carbon atoms in graphene is typically such that the sp bonds are mainly concentrated within the edges of graphene layers, and the sp 3 bonds generally connect the neighboring graphene layers to each other or form at their high-energy curved surfaces (FIG. 36A).
- the fraction of sp 2 bonds is at least one order of magnitude higher than the fractions of sp and sp 3 (see FIG. 44) bonds, indicating the dominance of sp 2 bonds, which is consistent with the above analyses from EELS.
- FIGs. 36B-36C present the compressive and tensile stress-strain response determined from the MD simulations and reveal similar trends and stresses to those in the experimental data.
- FIGs. 36D-36G depict several snapshots of the cross-section of a simulated deformed sample at different compressive strains.
- the curled graphene layers approached each other, and some bent significantly (FIG. 36D).
- FIG. 36D shows that As the applied compressive strain increased, several graphene layers slipped relative to the neighboring ones, which led to the abrupt fracture of the graphene layers under shear (FIGs. 36D-36E).
- Such discrete failure events gave rise to stress fluctuations in the mechanical response at a strain of 21.5%, as shown in FIG. 36B.
- FIGs. 36H-36J show a sequence of snapshots of the cross-section of a stretched sample at different strains.
- FIG. 361 and FIG. 45A we observed that a number of nanoscale cavities nucleated, expanded under tension, and then coalesced, leading to the formation of nanoscale cracks.
- FIG. 36J and FIG. 45B This cleavage fracture is similar to the experimental observations shown in FIG. 34E.
- FIG. 36C shows that the tensile strength of a nanopillar without initial cracks is above 20 GPa, which stems from the requirement for significant forces to break the strong covalent bonds.
- FIG. 46 shows the deformation processes of nanopillars with initial 4- and 8 nm-long nanocracks. We observe that their failure always originated from the growth and extension of the pre-existing nanocracks, leading to a smaller fracture strain and a smoother fracture surface than in nanopillars without nanocracks.
- the tensile strengths of the simulated samples are much higher than those of the experimental samples, which is a common phenomenon caused by a difference of approximately 10- 1 1 orders of magnitude in the applied strain rate, a difference of approximately 1-2 orders of magnitude in sample size and non-equivalent flaw concentrations in the experiments and simulations.
- the MD simulations also revealed some mechanistic details regarding the compression and tension of pyrolytic carbon pillars. During compression, the large deformation is accommodated by the closure of sub-nanometer- sized voids, densification of the structures and slipping/shear of the graphene layer fragments. Under tension, samples with initial flaws fail via the coalescence and extension of pre-existing flaws.
- the strength of the pyrolytic carbon micropillars is comparable to those of carbon microfibers 44 and gold nanowires (Au-NWs) 10 , but its density is approximately 79% and 7.3% of those of carbon fibers and Au-NWs, respectively.
- FIG. 47 shows an analogous property plot of the strength versus fracture strain for various materials, including shape memory zirconia 12 , SU-8 composites 14 , carbon microfibers 44 , GOP 41 , Cu-NPs 42 , NT-Cu 6 , and Zr- based metallic glasses (MG) 45 .
- the pyrolytic carbon micropillars in this work exhibit a superior combination of high strength and high deformability, which implies that they overcome the classical trade-off between strength and deformability that has plagued all materials to date.
- FIG. 37B shows the specific tensile and compressive strengths of various materials and reveals that the pyrolytic carbon micropillars have at least one order of magnitude greater specific strength than those of GOP, NT-Cu and Au-NWs, comparable to that of carbon microfibers.
- FIG. 37C shows an Ashby plot of specific strength versus fracture strain for our pyrolytic carbon and other various materials, including titanium alloys, magnesium alloys, carbon fiber reinforced polymer (CFRP) and diamond.
- our pyrolytic carbon occupies the unexplored space in the Ashby diagram, where no other materials reach.
- Our experiments and simulations revealed that pyrolytic carbon micropillars exhibit a unique combination of high deformability, an ultra-large elastic limit, and ultra-high strength and specific strength.
- curled graphene layers with a size of 1 nm have high in-plane rigidity and out-of-plane flexibility as well as high strength.
- the dense assembly of these graphene layers forms pyrolytic carbon micropillars via covalent bonding or van der Waals interactions.
- the pyrolytic carbon micropillars can sustain large elastic distortion and resist large compression and stretching.
- our pyrolytic carbon micropillars exhibit 1.5-8.2 times higher compressive strength and at least one order of magnitude larger fracture strain than existing bulk and micro-sized pyrolytic carbon 26 ⁇ 27 .
- These differences in mechanical properties can be attributed to differences in microstructures and sample sizes between these materials.
- both the crystallite size of the carbon layer fragments and spacing between neighboring layers in our pyrolytic carbon are much smaller than those (about 4-6 nm and 1.67-1.99 nm) of the existing bulk and micro-sized pyrolytic carbon 26 ⁇ 27 .
- These different micro structures are induced by different pyrolysis precursor materials and conditions (such as temperature and duration time).
- our pyrolytic carbon with high strength and large deformability are several microns in diameters, which are 2- 4 orders of magnitude smaller than diameters (beyond hundreds of microns) of bulk and micro-sized pyrolytic carbon 26 ⁇ 27 . Therefore, designing/controlling atomic-level microstructures and sample dimension have resulted in significant enhancement of the mechanical properties of pyrolytic carbon.
- micropillars derived from a polymeric photoresist via DLW and pyrolysis. These micropillars consist of curled graphene fragments with an average size of approximately 1.0-1.5 nm.
- Fabrication of samples The fabrication process of pyrolytic carbon micropillars includes two steps: two-photon lithography and high-temperature pyrolysis. We first synthesized the pillars using 3D TPL DLW (Photonic Professional, Nanoscribe GmbH) with the dip-in laser lithography configuration, a 63x objective and commercial IP-Dip photoresist. For pyrolysis, the printed polymeric samples were heated to 900 °C at a ramp rate of 7.5 °C min 1 in a vacuum tube furnace, then maintained at the target temperature for 5 hours, and finally cooled to the room temperature at a natural rate.
- 3D TPL DLW Photonic Professional, Nanoscribe GmbH
- the pillar dimensions shrank to approximately 20%-25% of their original values, which corresponds to a 98% volumetric contraction.
- the diameter D of the pyrolytic carbon pillars for the compression experiments varied from 1 .28 to 12.7 pm. Dog-bone shaped samples with gauge sections of 0.7 to 2.0 pm were also synthesized using the same procedure for the tensile experiments.
- the aspect ratios (i.e., height to diameter) of the pyrolytic carbon samples were 1 .4-1 .8 for compression and 1.5-4.3 for tension.
- Microstructural characterization The microstructure of the pyrolytic carbon micropillars was characterized by an FEI Technai TF-30 TEM at an accelerating voltage of 300 kV. EELS was conducted in an FEI Technai TF-20 at an accelerating voltage of 200 kV to estimate the relative fractions of sp 2 and sp 3 bonds. Samples for TEM analyses were prepared using a site-specific lift-out procedure, attaching the detached lamella to the TEM grid, and final thinning to a final thickness of 60.73 nm using a voltage of 15 kV and a current of 10 pA in the focused ion beam (FIB, FEI Versa). Raman spectra were collected at room temperature using a Raman spectrometer (Renishaw M1000 Micro) with a 514.5 nm laser.
- Nanomechanical experiments Uniaxial compression on samples with diameters of 1.28-2.28 pm and all uniaxial tension experiments were conducted at a constant nominal strain rate of 10 -3 s -1 in a custom-made in situ nanomechanical instrument (SEMentor) 33 with a 10 pm-diameter flat punch indenter tip. Samples with larger diameters of 4.6-12.7 pm were compressed in a nanoindenter (Nanoindenter G200 XP, Agilent/Keysight Technologies) with a 120 pm-diameter flat punch at a constant loading rate of 0.02-0.2 mN s 1 because of the load limit in the in situ instrument. Additional compression experiments were conducted on samples with diameters of 2.21-12.7 pm in the G200 to independently validate the results of the in situ experiments.
- FIG. 41 provides a comprehensive set of images that pertain to the estimation of density in these materials.
- FIG. 41 , panel (a) illustrates the distribution of the curved graphene segments
- FIG. 41 , panel (b) shows an individual representative graphene segment, where the average end-to-end length is L and the spacing between neighboring layers L s .
- the density of the curved graphene layers, PCGL can be expressed as
- FIG. 41 panel (c), is a schematic that represents a reasonable stacking structure of two curved graphene layers. Using this geometry as a guide, the density of pyrolytic carbon can be estimated as 26
- Raman spectroscopy is widely used to investigate defects and disorder in carbon materials at the nanoscale level, including graphene, carbon nanotubes and glassy carbon 31 ’ 47 .
- the ratio of the integrated area under the D peak and that under the G peak, ID/IG, in a Raman spectrum is related to the in-plane crystallite size (L) of carbon materials by Eq. (1 ) 31 .
- EELS spectra provide quantitative information about the electronic structure of carbon materials 27 ’ 32 .
- a normalized ratio L/ t can then be calculated as 27 32
- Atomistic simulations We performed a series of large-scale atomistic simulations that emulate the uniaxial compression and tension of pyrolytic carbon nanopillars using LAMMPS 37 .
- Example 9 Lightweight, flaw tolerant and strong nano-architected carbon
- thermomechanical environments We discuss this combination of high specific strength, low density, and extensive deformability prior to failure in the context of interplay among atomic-level microstructure of pyrolytic carbon, nano-sized beam dimensions, and optimized lattice topology.
- a general guideline for a material to be considered“lightweight” is for its density to be less than that of water (i.e. , p£ 1 .0 g/cm 3 ) (16).
- Recent breakthroughs in material processing techniques, especially in three-dimensional (3D) microfabrication and additive manufacturing provide a particularly promising pathway to fabricate lightweight materials, which often possess a suite of other beneficial properties like high specific stiffness, high specific strength and good resilience/recoverability (7-27).
- the penalty for the ultra light weight in these nano- and micro-architected materials is a severe reduction in their stiffness and strength through power law scaling: a ⁇ plps) m , E ⁇ (p/ps) n , where s n is the yield strength, E is the Young’s modulus, p is the density, and P s is the density of the fully-dense constituent solid (1 ).
- the exponents m and n are generally greater than 1 , which renders developing methodologies to create materials that are simultaneously lightweight and strong/stiff, while maintaining their other properties - i.e. thermal stability, electrical conductivity, magnetism, recoverability, etc. - a grand unsolved challenge because of the restricted material choices and limited architectures.
- micro-/nano- architected materials have a common feature of length scale hierarchy, i.e. relevant dimensions of their structural elements span 3-5 orders of magnitude, from tens of nanometers to hundreds of micrometers and even greater.
- Structural features of nickel-alloy hollow-tube nanolattices fabricated using large-area projection microstereolithography span 7 orders of magnitude in spatial dimensions, from tens of nanometers to tens of centimeters, and attained tensile strains of >20% with a low modulus of 125 kPa and a low tensile strength of -80 kPa at a density of -0.20 g/cm 3 , which corresponds to the relative density of 0.15% (17).
- 3D periodic graphene aerogel microlattices have been synthesized via direct ink writing; these materials are exceptionally lightweight, with a density of 0.031 -0.123 g/cm 3 , very compliant, with a modulus of 1 -10 MPa, and weak, with a low strength of 0.10-1.6 MPa, and exhibit nearly complete recovery after compression to 90% strain (23).
- Octet-truss nanolattices made up of 262-774 nm-diameter polymer beams with sputtered 14-126 nm-thick high- entropy alloy (HEA)-coatings were reported to have a Young’s modulus of 16-95 MPa and a compressive strength of 1-10 MPa at densities between 0.087 and 0.865 g/cm 3 (20). Samples with HEA thicknesses of less than 50 nm completely recovered after > 50% compressions (20). Beyond core-shell-beamed nano- and micro-architected materials, several reports exist on the fabrication and deformation of 3D structural meta- materials with monolithic beams.
- HEA high- entropy alloy
- nanocrystalline nickel octet-truss nanolattices with 300-400 nm-diameter monolithic beams and 2 pm unit cells created via TPL on custom-synthesized resins followed by pyrolisis exhibited a modulus of ⁇ 90 MPa, a compressive strength of 18 MPa, a high fracture strain of >20% at a density of 2.5 g/cm 3 (20).
- Glassy carbon nanolattices with tetrahedral unit cells created via TPL and pyrolysis had smaller dimensions, 0.97-2.02 pm unit cells and beam diameters of -200 nm, a modulus of 3.2 GPa and a compressive strength of -280 MPa at a density of -0.35 g/cm 3 (18).
- octet- and iso-truss shown in FIGs. 48A-48F, using two-photon lithography and pyrolysis.
- the octet-truss architecture has cubic anisotropy and superior overall properties compared to other conventional lattices, such as triangular, tetrahedral, or cubic trusses and foams (28), while the iso-truss structure is isotropic and has been theorized to possess optimal stiffness compared to traditional lattice topologies (29).
- FIG. 48A illustrates the fabrication process, which begins with printing 5x5x5 unit cells microlattices out of IP-Dip photoresist using TPL.
- the polymer samples were then heated in a vacuum furnace at a ramp rate of 7.5 °C min 1 up to 900 °C, pyrolyzed for 5 hours, and cooled down to room temperature at a natural rate (see Methods for more details).
- FIGs. 48B and 48D show CAD designs of 10 pm-sized octet- and iso-truss unit cells.
- Strut diameters d in the octet-truss were designed to be 0.8-2.4 pm.
- the vertical strut diameters d t were 1.4-3.0 pm
- the polymer After pyrolysis, the polymer transformed into a form of carbon and underwent significant volumetric shrinkage and mass loss (30). Each strut shrunk to ⁇ 20%-25% of its initial dimensions (FIGs.
- FIG. 48E shows that the cfc/cfi is preserved at -1.14 after pyrolysis, which suggests uniform volume shrinkage.
- FIG. 48F shows a high-resolution transmission electron microscopy
- FIGs. 49A and 49B convey the compressive stress-strain response of some representative octet- and iso-truss pyrolytic carbon nanolattices, which appear to be similar across all samples.
- FIG. 53A-53H show the compressive stress-strain data of typical polymer microlattices with octet- (FIG. 53A) and iso-truss (FIG. 53E) unit cells for comparison and completeness.
- This data also has the initial nonlinear region over -2.5% strain caused by the slightly imperfect initial contact and misalignment between the rough lattice surfaces and the flat punch (16).
- Linear elastic loading commences over the strain range of ⁇ 2.5-7.5% followed by plastic deformation, followed by a stress plateau that extends over 5-7.5%. Such stress plateau corresponds to buckling of the struts, as evidenced by SEM images (FIG. 53C and 53G).
- Table 1 summarizes the Young’s moduli and strengths of the tested polymeric microlattices with different relative densities and reveals that for comparable relative densities, the Young’s modulus of iso- truss microlattices is a factor of ⁇ 2, and the strength is 1 3x higher than those of the octet-truss microlattices, consistent with predictions (29).
- FIGs. 50A-50B show the material property space for Young’s modulus (FIG.
- FIGs. 54A and 54B show the variations of Young’s modulus and compressive strength with the relative density, respectively.
- our pyrolytic carbon nanolattices have the scaling relations of Young’s modulus as E ⁇ p 2 ⁇ 25 for the octet-truss and E ⁇ > 1 90 for the iso-truss, and those of compressive strength as s n ⁇ g> 2 41 for the octet-truss and s n ⁇ g> 2 50 for the iso-truss.
- These scaling relations deviate from theoretical predictions for ideal, stretching-dominated structures (1 ), i.e.
- FIGs. 49C and 49E show some of the representative detectable fabrication-induced defects that we found to be present in virtually all samples, including beam junction offsets and bulges, slight curvature of the struts, and micro-pits and voids. During compression, these
- the nodes generally form solid joints that impede beam rotation and, to some extent, shorten the effective length of the adjoining beams and lead to stiffening of overall lattices (12).
- the recent computational and experimental studies found that for solid-beam octet-truss lattices, with a beam slenderness ratio greater than 0.06 and the corresponding relative density beyond 10%, the scaling relations for modulus and strength diverge from existing analytic theories, with the exponents of 2.20 and 1.88 instead of 1.0 (12).
- the beam slenderness ratios, R/L , of the octet-truss nanolattices in this work are 0.07-0.24, similar to 0.07-0.12 of the monolithic polymer octet-truss nanolattices (12), as well as to 0.06-0.20 of glassy carbon nanolattices with tetrahedral unit cells (18).
- the scaling exponents of 2.25 (octet-truss) and 1 .90 (iso-truss) for Young’s modulus and of 2.41 (octet-truss) and 2.50 (iso-truss) for strength found for nano-architected carbon with a relative density between 15% and 80% in this work agree with these existing report (12).
- FIGs. 50A-50B convey that these relatively high scaling exponents for the mechanical attributes of pyrolytic carbon nanolattices lead to highest stiffness and strength reported to date (1 1 ,18).
- FIGS. 51A-51 C show the simulated nanolattices with different unit cells, where pre-existing defects were created by imposing the corresponding buckling eigenmodes with a maximum deflection of the struts prescribed as 5%, 10% and 15% of the edge length, similar to (18). After introducing these initial deflections, some struts remained pre-bent before compression, which resembles structural imperfections in the experimental samples (FIGs. 49C and 49E). We also simulated the compression of a perfect nanolattice as a reference.
- FIGs. 51 D-51 F show the compressive stress-strain response up to 12% strain of simulated nanolattices and reveals that the strengths of nanolattices with initial deflection are always lower than those of their perfect counterparts.
- FIG. 51 D-51 F show the compressive stress-strain response up to 12% strain of simulated nanolattices and reveals that the strengths of nanolattices with initial deflection are always lower than those of their perfect counterparts.
- FIGs. 56A- 56B quantify the variation in strength reduction as a function of initial deflection relative to that of a perfect nanolattice and indicates that (i) for a given relative density and architecture, the relative reduction in strength increases with greater initial deflection; (ii) for a given architecture, the nanolattices with higher densities experience smaller relative weakening with defects; and (iii) nanolattices with tetrahedron-truss unit cells are most susceptible to flaws, followed by octet-truss and iso-truss for all densities.
- the relative reduction in strength is 2% for the iso-truss and 15% for the octet-truss architectures at a maximum deflection of 15%.
- the same relative weakening for a relative density of 70% is only ⁇ 1 %.
- the struts When the struts’ diameter is reduced by hundreds of nanometers to dimensions comparable to the critical size for flaw insensitivity of constitute, the struts exhibit high strength and good flaw tolerance, which to some extent contributes to the high strength of carbon nanolattices, which is dictated by local stresses and the volume fractions of the struts (4). Nanolattices with lower densities have thinner and more slender struts, which leads to higher local stresses during compression due to their smaller cross-sectional areas, and the nodal contributions are negligible (12,37). In this case, the higher local stresses lead to earlier buckling of some struts or higher stress concertation around the nodes.
- the nanolattices with lower densities might fail at lower global stresses.
- nanolattices with higher densities i.e. thicker struts
- the nanolattices with higher densities have lower local stresses because of the greater cross- sectional area in each strut, with significant contribution of the nodes to the load-bearing ability, which results in a relatively uniform distribution of applied load throughout the nanolattice (12,37).
- the nanolattices fail when the local stresses in the struts approach the theoretical strength of constitute carbon.
- Such local stress and higher volume fraction of struts eventually result in high strength of nanolattices at higher densities.
- the optimized unit-cell geometries, such as octet- and iso-truss, with better flaw tolerance also facilitate the achievement of high strength.
- FIG. 52 shows that the specific strengths of pyrolytic carbon nanolattices range from 0.146 to 1 .90 GPa g -1 cm 3 , which represents 2-3 orders of magnitude improvement over all nano- and micro-architected periodic lattices reported to date, including hollow-tube nickel (7) and NiP (8), copper (19), and T ⁇ AIb L (27) microlattices, as well as of hollow-beam alumina (1 1 ), alumina-polymer (16) and metallic glass ZG5 4 N ⁇ 2 d AI ⁇ 8 nanolattices (33).
- the maximum specific strength of the carbon nanolattices in this work is 2.4 times higher than that of 0.80 GPa g -1 cm 3 reported for glassy carbon nanolattices (18) , and represents 35% of fully-dense diamond, at 5.60 GPa g -1 cm 3 , which has the highest specific strength of all bulk materials (18).
- Such ultra-high specific strength of our pyrolytic carbon nanolattices arises from both the nano-sized beam diameters and the optimized lattice topology.
- characteristic materials dimensions enabled us to create prototype architectures of octet- and iso-truss pyrolytic carbon nanolattices with a Young’s modulus of 0.34-18.6 GPa and strengths of 0.05-1.90 GPa at densities of 0.24-1.0 g/cm 3 , which translates into a specific strength of 0.146-1.90 GPa g -1 cm 3 that has not been attained by any carbon- based or architected material.
- This nano-architected carbon also exhibited average fracture strains of 14.0%-16.7%, exceeding those of all other reported brittle architected materials.
- the unit-cell size of polymeric microlattices is about 10 pm. Then the polymeric microlattices were pyrolized at 900 °C for 5 hours in a vacuum, with a ramp rate of 7.5 °C min -1 up to the target temperature and then cooled down to room temperature at a natural rate. After pyrolysis, the polymeric microlattices transformed into pyrolytic carbon nanolattices, due to the mass-loss-induced carbonation of the polymers at elevated temperature (30). The diameters of all struts in pyrolytic carbon nanolattices isotropically shrunk to about 261-679 nm, which is about 20%-25% of their initial dimensions (FIGs. 48C and 48E). The unit-cell size of all pyrolytic carbon nanolattices is about 2 pm.
- Finite element modelling We carried out a series of FE modelling for the compression of pyrolytic carbon nanolattices via Abaqus.
- the isotropic linear elastic material was used for modelling. All nanolattices were modeled with beam element.
- the Young’s modulus of material is 20 GPa (34) and the Poisson’s ratio was 0.15 (18).
- the simulated nanolattices have three types of unit-cell geometries, including octet-truss, iso-truss and tetrahedron-truss. For each type of nanolattice, the unit-cell size sets to be 2 pm, and the relative density varies from 15.9% to 70% by alternating the diameter of struts.
- the strength- density limit is defined in the literature (18) and just a specific range based on the measurements for all materials to date.
- the lower bound of this range is defined by diamond, which has the highest specific strength of all bulk materials, while the upper bound is determined by graphene, which holds the highest strength in all materials so far.
- Meza LR Das S, Greer JR (2014) Strong, lightweight, and recoverable three- dimensional ceramic nanolattices. Science 345:1322-1326. 12. Meza LR, Phlipot GP, Portela CM, Maggi A, Montemayor LC, Cornelia A, Kochmann
- Example 10 Scalable fabrication method of 3D architected structure using additive manufacturing and pyrolysis thereof
- FIGs. 57A-57D exhibit characterizations of the microstructure of the 3D architected carbon.
- a cross-section image of the 3D architected carbon, shown in FIG. 57A, demonstrates its monolithic structure without any micropores.
- EDS analysis on the cross-section surface showed that the 3D architected carbon was composed of 98.4% carbon in an average with minor content of oxygen.
- Line analysis showed homogeneous elemental composition across the cross-section (FIG. 58A).
- FIG. 57B shows XRD patterns with three broad peaks at 23.5°, 44.3° and 79.8° in 2Q, corresponding to (002), (100)/(101 ) and (1 10) of graphite.
- the average interlayer spacing for graphene sheets and crystallite size along (002) (i.e. d 00 2 and L c ) were estimated to be 3.78 A and 9.3 A using the Bragg’s law and Scherrer equation respectively, which suggested that there existed several stacked graphitic layers in average.
- Raman spectra shown in FIG. 57C, was deconvoluted into five peaks: strong peaks of D1 (at 1355 cm 1 ) and G (at 1603 cm 1 ) and weak peaks of D2 (at 1613 cm 1 ), D3 (at 1539 cm 1 ) and D4 (1225 cm 1 ).
- the G peak corresponds to in-plane bond-stretching motion of pairs of C sp 2 atoms with E 2g symmetry.
- the D1 peak appears only in the presence of the disorder of graphite and corresponds to a graphitic lattice vibration mode with Ai g symmetry. 24 The D2 peak was considered attributed to a graphitic lattice vibration, and D3 and D4 peaks have been seen in amorphous or glassy carbon in other studies. 25 26 The high-resolution image of TEM in FIG. 57D confirmed the tangled microstructure containing several stacked graphitic layers. Diffused diffraction rings at (002), (100)/(101 ) and (1 10) in the inset illustrated disordered carbon micro structure, which agreed with broad peaks of the XRD pattern.
- FIGs. 59A-59B show representative mechanical response with in-situ compression side-views of a part of the architecture around each collapse event (full movie is accessible in Supplemental). Note that the bottom side of the 3D architecture was chipped when removing it from a substrate of the DLP 3D printer.
- the first stress release was followed by the gradual decrease of the load with local failure events as pointed by red circles in FIG. 59B ll-a, ll-b, and ll-c.
- the second stress release event occurred when the contact part of 3D architected carbon on the substrate was fractured by a half layer (FIG. 59B IV).
- the 3D architected carbon was almost fully contacted on the substrate and collapsed by a half layer with showing the largest yield stress (29.9MPa). These two collapse events with small yield strength and the subsequent third collapse with high strength were repeatedly observed (FIG. 60). Average yield strengths at each stress release event were tabulated in Table 2.
- Example 1 1 Node Free Geometries
- FIG. 61 A and FIG. 61 B Images showing architected three-dimensional structures having node-free geometries, according to certain embodiments of the invention. Additional exemplary node-free geometries may be found in Abueidda, et al. (“Effective conductivities and elastic moduli of novel foams with triply periodic minimal surfaces”, Mechanics of Materials, vol. 95, April 2016, pages 102-1 15), which is incorporated herein by reference.
- Example 12 Infiltration of Carbon Reinforcing Phases
- SEA specific energy absorption
- any one or more hydrogens in a molecule disclosed can be replaced with deuterium or tritium.
- Isotopic variants of a molecule are generally useful as standards in assays for the molecule and in chemical and biological research related to the molecule or its use. Methods for making such isotopic variants are known in the art. Specific names of compounds are intended to be exemplary, as it is known that one of ordinary skill in the art can name the same compounds differently. [0342] Every system, structure, geometry, feature, combination thereof, or method described or exemplified herein can be used to practice the invention, unless otherwise stated.
- composition of matter when composition of matter are claimed, it should be understood that compounds known and available in the art prior to Applicant's invention, including compounds for which an enabling disclosure is provided in the references cited herein, are not intended to be included in the composition of matter claims herein.
Abstract
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AU2018424951A AU2018424951A1 (en) | 2017-12-01 | 2018-11-30 | Fabrication and design of composites with architected layers |
CA3082841A CA3082841A1 (en) | 2017-12-01 | 2018-11-30 | Fabrication and design of composites with architected layers |
EP18920051.2A EP3718159A4 (en) | 2017-12-01 | 2018-11-30 | Fabrication and design of composites with architected layers |
JP2020529530A JP2021505429A (en) | 2017-12-01 | 2018-11-30 | Manufacture and design of composites with build-up layers |
KR1020207018323A KR20200084358A (en) | 2017-12-01 | 2018-11-30 | Fabrication and design of composites with architecture layers |
IL274970A IL274970A (en) | 2017-12-01 | 2020-05-27 | Fabrication and design of composites with architected layers |
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US16/151,186 US10833318B2 (en) | 2017-10-03 | 2018-10-03 | Three-dimensional architected pyrolyzed electrodes for use in secondary batteries and methods of making three-dimensional architected electrodes |
US16/151,186 | 2018-10-03 |
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