Granular feedstock for additive manufacturing of ceramic parts

Abstract

The present disclosure provides a method of manufacturing a ceramic matrix composite (CMC) component. The method may include constructing a plurality of contiguous layers of the ceramic component by selective consolidation of a composite feedstock comprising a plurality of composite particles, and densifying the ceramic component by silicon infiltration. Each of the plurality of composite particles includes one or more silicon carbide particles and one or more carbon particles. The present disclosure also provides a composite feedstock that may include a plurality of composite particles, each of the plurality of composite particles including one or more silicon carbide particles and one or more carbon particles.

Description

Technical Field

[0001] The present disclosure relates to additively manufacturing ceramic-based components. Background Art

[0002] Reinforced ceramic matrix composites ("CMCs") comprising fibers dispersed in a continuous ceramic matrix of the same or different composition are well suited for structural applications due to their toughness, heat resistance, high temperature strength, and chemical stability. Such composites typically have a high strength-to-weight ratio and are able to maintain this property over a wider operating temperature range than superalloys. This makes them attractive in high temperature applications where weight is a concern, such as in aerospace applications involving high temperature structures. The stability of CMCs at high temperatures also makes them well suited for applications where the components are in contact with hot gases, such as gas turbine engines. Summary of the invention

[0003] A method of manufacturing a ceramic matrix composite (CMC) component, the method comprising: building a plurality of successive layers of the CMC component by selective consolidation of a composite feedstock comprising a plurality of composite particles, wherein each of the plurality of composite particles comprises one or more silicon carbide particles and one or more carbon particles; and

[0004] Densification of CMC parts by silicon infiltration.

[0005] A method according to the preceding clause, wherein each of the plurality of composite particles further comprises a binder.

[0006] A method according to any of the preceding clauses, wherein each of the plurality of composite particles further comprises silicon.

[0007] A method according to any of the preceding clauses, wherein the composite feedstock comprises 50 to 95 wt% silicon carbide.

[0008] A method according to any of the preceding clauses, wherein the composite feedstock comprises 5 to 50 wt% carbon.

[0009] A method according to any of the preceding clauses, wherein the composite feedstock comprises 5 to 35 wt% silicon.

[0010] A method according to any of the preceding clauses, wherein the average particle size of the plurality of composite particles of the composite feedstock is from 5 μm to 75 μm.

[0011] A method according to any of the preceding clauses, wherein the method further comprises combining a plurality of silicon carbide particles with a plurality of carbon particles to form a plurality of composite particles.

[0012] The method according to any of the preceding clauses, wherein the plurality of silicon carbide particles have an average particle size of 0.1 μm to 10 μm.

[0013] The method according to any of the preceding clauses, wherein the average particle size of the plurality of carbon particles is from 0.1 μm to 10 μm.

[0014] A method according to any of the preceding clauses, wherein building the plurality of successive layers of the CMC component comprises curing the composite feedstock by binder jet printing or digital light processing.

[0015] The method of any of the preceding clauses, wherein densifying the CMC component comprises melt infiltration or chemical vapor infiltration using molten silicon.

[0016] A method according to any of the preceding clauses, wherein the method further comprises laying up one or more composite layers on the CMC component, and joining the one or more composite layers to form the CMC component.

[0017] The method according to any of the preceding clauses, wherein the CMC component is a turbine component.

[0018] A method of manufacturing a ceramic matrix composite (CMC) component, the method comprising: building a plurality of successive layers of the CMC component by selective consolidation of a composite feedstock, wherein the composite feedstock comprises a plurality of composite particles formed from a combination of one or more silicon carbide particles and one or more carbon particles, the composite feedstock comprising 5 to 95 weight percent silicon carbide and 5 to 40 weight percent carbon; and

[0019] The CMC parts are densified by infiltration using silicon or silicon-containing reactants.

[0020] A method according to any of the preceding clauses, wherein the composite feedstock further comprises 5 to 35 wt% silicon.

[0021] A method according to any of the preceding clauses, wherein the average particle size of the plurality of composite particles of the composite feedstock is from 5 μm to 75 μm.

[0022] A composite raw material comprising:

[0023] a plurality of composite particles, each of the plurality of composite particles comprising one or more silicon carbide particles and one or more carbon particles;

[0024] The composite feedstock comprises 5 to 95 weight percent silicon carbide and 5 to 40 weight percent carbon; and

[0025] The average particle size of the plurality of composite particles of the composite raw material is 5 μm to 75 μm.

[0026] A method according to any of the preceding clauses, wherein one or more of the plurality of composite particles further comprises a binder.

[0027] A method according to any of the preceding clauses, wherein one or more of the plurality of composite particles further comprises silicon. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The specification sets forth a complete and enabling disclosure of the present disclosure, including the best mode thereof, for one of ordinary skill in the art, wherein:

[0029] Figure 1 is a schematic cross-sectional view of a gas turbine engine according to an exemplary aspect of the present disclosure.

[0030] Figure 2 A is a schematic diagram of a silicon carbide pellet as an exemplary source material for producing a composite feedstock according to an exemplary aspect of the present disclosure.

[0031] Figure 2 B is a plurality of silicon carbide particles (e.g., from Figure 2 Schematic diagram of the silicon carbide spherical particles shown in A).

[0032] Figure 2 C is a plurality of silicon carbide particles (e.g. Figure 2 Schematic diagram of multiple silicon carbide particles in B).

[0033] Figure 2 D is a combination of one or more silicon carbide particles and one or more carbon particles (e.g. Figure 2 Schematic diagram of a composite particle formed by a combination of one or more silicon carbide particles and one or more carbon particles (as shown in C).

[0034] Figure 2 E is a plurality of composite particles (e.g. Figure 2 Schematic diagram of the composite particle shown in D).

[0035] Figure 3 is an exploded perspective view of an exemplary ceramic component according to an exemplary aspect of the present disclosure.

[0036] Figure 4 A flow chart is provided that illustrates an exemplary method of additively manufacturing a ceramic component according to an exemplary aspect of the present disclosure. DETAILED DESCRIPTION

[0037] Reference will now be made in detail to the present embodiments of the present disclosure, one or more examples of which are shown in the accompanying drawings. The detailed description uses numerical and letter designations to refer to features in the drawings. The same or similar designations in the drawings and description have been used to refer to the same or similar parts of the present disclosure.

[0038] As used herein, the word "exemplary" means "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations. Furthermore, unless expressly stated otherwise, all implementations described herein should be considered exemplary.

[0039] The singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0040] In the case of, for example, “at least one of A, B, and C,” the term “at least one” means only A, only B, only C, or any combination of A, B, and C.

[0041] The term "gas turbine engine" refers to an engine having a turbine as all or part of its power source. Exemplary gas turbine engines include turbofan engines, turboprop engines, turbojets, turboshaft engines, etc., as well as hybrid electric versions of more than one of these engines.

[0042] The term "turbomachine" refers to a machine that includes one or more compressors, heat generating sections (eg, combustion sections), and one or more turbines that together produce a torque output.

[0043] The term "combustion section" refers to any heat increase system of a turbine. For example, the term "combustion section" may refer to a section that includes one or more of a deflagration combustion device, a rotating detonation combustion device, a pulse detonation combustion device, or other suitable heat increase devices. In certain exemplary embodiments, the combustion section may include an annular combustion chamber, a can combustion chamber, a tube combustion chamber, a trapped vortex combustion chamber (TVC), or other suitable combustion systems, or combinations thereof.

[0044] The terms "low" and "high" or their respective comparatives (e.g., more-, where applicable) when used with a compressor, turbine, shaft or spool component, etc., each refers to a relative speed within the engine unless otherwise specified. For example, a "low turbine" or "low-speed turbine" defines a component that is configured to operate at a lower speed (e.g., maximum allowable speed) than a "high turbine" or "high-speed turbine" of the engine.

[0045] The terms "front" and "rear" refer to relative positions within a gas turbine engine or vehicle and refer to the normal operating attitude of the gas turbine engine or vehicle. For example, for a gas turbine engine, "front" refers to a position closer to the engine inlet and "rear" refers to a position closer to the engine nozzle or exhaust.

[0046] The terms "upstream" and "downstream" refer to relative directions with respect to fluid flow in a fluid channel. For example, "upstream" refers to the direction from which the fluid is flowing, and "downstream" refers to the direction toward which the fluid is flowing.

[0047] As used herein, the terms "axial" and "axial direction" refer to directions and orientations extending substantially parallel to the centerline of the gas turbine engine. Additionally, the terms "radial" and "radial direction" refer to directions and orientations extending substantially perpendicular to the centerline of the gas turbine engine. Additionally, as used herein, the terms "circumferential" and "circumferential direction" refer to directions and orientations extending in an arc around the centerline of the gas turbine engine.

[0048] Common chemical abbreviations of chemical elements (such as common chemical abbreviations of the periodic table) are used in this disclosure to discuss the chemical elements. For example, hydrogen is represented by its common chemical abbreviation H, helium is represented by its common chemical abbreviation He, and so on.

[0049] As used herein, the term "composite material" refers to a material made of two or more constituent materials, at least one of which is a non-metallic material. Exemplary composite materials include polymer matrix composites (PMC), ceramic matrix composites (CMC), chopped fiber composites, etc.

[0050] As used herein, ceramic matrix composites or "CMCs" refer to a class of materials that include reinforcement materials (e.g., reinforcing fibers) surrounded by a ceramic matrix. Typically, the reinforcing fibers provide structural integrity to the ceramic matrix. Some examples of matrix materials for CMCs may include, but are not limited to, non-oxide silicon-based materials (e.g., silicon carbide, silicon nitride, or mixtures thereof), oxide ceramics (e.g., silicon oxycarbide, silicon oxynitride, aluminum oxide (Al2O3), silicon dioxide (SiO2), aluminosilicates, or mixtures thereof), or mixtures thereof. Optionally, the CMC matrix may also include ceramic particles (e.g., oxides of Si, Al, Zr, Y, and combinations thereof) and inorganic fillers (e.g., pyrophyllite, wollastonite, mica, talc, kyanite, and montmorillonite).

[0051] Some examples of reinforcing fibers for CMCs may include, but are not limited to, non-oxide silicon-based materials (e.g., silicon carbide, silicon nitride, or mixtures thereof), non-oxide carbon-based materials (e.g., carbon), oxide ceramics (e.g., silicon oxycarbide, silicon oxynitride, aluminum oxide (Al2O3), silicon dioxide (SiO2), aluminosilicates (e.g., mullite), or mixtures thereof), or mixtures thereof.

[0052] In general, specific CMCs may be referred to as their fiber type / matrix type combination. For example, carbon fiber reinforced silicon carbide is C / SiC, silicon carbide fiber reinforced silicon carbide is SiC / SiC, silicon carbide fiber reinforced silicon nitride is SiC / SiN, silicon carbide fiber reinforced silicon carbide / silicon nitride matrix mixture is SiC / SiC-SiN, etc. In other examples, CMCs may include a matrix and reinforcing fibers, the reinforcing fibers including oxide-based materials such as aluminum oxide (Al2O3), silicon dioxide (SiO2), aluminosilicates, and mixtures thereof. Aluminosilicates may include crystalline materials such as mullite (3Al2O3·2SiO2) and glassy aluminosilicates.

[0053] In certain embodiments, the reinforcing fibers may be bundled and / or coated before being included in the matrix. For example, the fiber bundles may be formed into reinforcing tapes, such as unidirectional reinforcing tapes. Multiple tapes may be laid together to form a preformed component. The fiber bundles may be impregnated with a slurry composition before or after forming the preform. The preform may then be heat treated and subsequently chemically treated to obtain a component formed of a CMC material having a desired chemical composition. For example, the preform may be cured or burned out to produce a high carbon residue in the preform, followed by melt infiltration with silicon, or cured or pyrolyzed to produce a silicon carbide matrix in the preform, or subsequently chemically infiltrated with silicon carbide. Before or after chemical vapor infiltration, other steps may be taken to improve the densification of the preform, which is performed by injecting a liquid resin or polymer into the preform, followed by a heat treatment step to fill the voids with silicon carbide. The CMC materials used herein may be formed using any known or hereafter developed method including, but not limited to, melt infiltration, chemical vapor infiltration, polymer infiltration pyrolysis (PIP), or any combination thereof.

[0054] Such materials, along with certain monolithic ceramics (i.e., ceramic materials without reinforcement materials), are particularly well suited for higher temperature applications. In addition, these ceramic materials are lightweight compared to superalloys, yet still provide strength and durability to components made therefrom. As a result, such materials are currently being considered for use in many gas turbine components used in the higher temperature sections of gas turbine engines, such as airfoils (e.g., turbines and blades), combustors, shrouds, structural elements of thermal protection systems, aerodynamic control surfaces (e.g., vanes), or other similar components that would benefit from the lighter weight and higher temperature performance that these materials can provide.

[0055] As described herein, the subject matter of the present disclosure relates to the application of additive manufacturing machines or systems. As used herein, the term "additive manufacturing" generally refers to a manufacturing technique for manufacturing parts in a layer-by-layer manner. An exemplary additive manufacturing machine can be configured to utilize any suitable additive manufacturing technology. Additive manufacturing technologies that can be utilized by additive manufacturing machines include powder bed fusion (PBF) technology, such as direct metal laser melting (DMLM) technology, selective laser melting (SLM) technology, direct metal laser sintering (DMLS) technology, or selective laser sintering (SLS) technology. In the exemplary PBF technology, thin layers of powder material are applied sequentially to a build plane and then selectively melted or fused to each other in a layer-by-layer manner to form more than one three-dimensional object. Additively manufactured objects are typically monolithic in nature and can have various integrated sub-components.

[0056] Additionally or alternatively, suitable additive manufacturing techniques may include, for example, fused deposition modeling (FDM) techniques, direct energy deposition (DED) techniques, laser engineered net shaping (LENS) techniques, laser net shaping manufacturing (LNSM) techniques, direct metal deposition (DMD) techniques, digital light processing (DLP) techniques, binder jet printing (BJP) and other additive manufacturing techniques that utilize energy beams or other energy sources to bond or solidify additive manufacturing materials (e.g., powder materials) into shape. In fact, any suitable additive manufacturing mode may be used with the subject matter of the present disclosure.

[0057] Additive manufacturing techniques can generally be described as manufacturing an object by building the object point by point, line by line, or layer by layer, usually in a vertical direction. Other manufacturing methods are contemplated and within the scope of the present disclosure. For example, although the discussion herein relates to adding material to form successive layers, the subject matter of the present disclosure can be practiced with any additive manufacturing technique or other manufacturing technique, including a layer-additive process, a layer-subtractive process, or a hybrid process.

[0058] The additive manufacturing methods described herein can be used to form parts using any suitable material. For example, the material can be a metal, a ceramic, a polymer, an epoxy resin, a photopolymer resin, a plastic, or any other suitable material, and the material can be a solid, a powder, a sheet material, a wire, or any other suitable form, or a combination thereof. Additionally or alternatively, exemplary materials may include metals, ceramics, or adhesives, and combinations thereof. Exemplary ceramics may include ultra-high temperature ceramics and / or precursors to ultra-high temperature ceramics, such as polymer precursors. Each continuous layer may be, for example, about 10 μm to 200 μm, but the thickness may be determined based on any number of parameters and may be of any suitable size.

[0059] As used herein, the term "build plane" refers to a plane defined by a surface onto which an energy beam impinges to selectively irradiate and thereby bond or consolidate powdered material during an additive manufacturing process. Typically, the build plane is defined by the surface of a powder bed. During irradiation of a respective layer of the powder bed, a previously irradiated portion of the respective layer may define a portion of the build plane. Prior to distributing the powdered material on a build module, the build plane is typically defined by a build plate that supports the powder bed.

[0060] As used herein, the term "consolidate" or "consolidate" refers to consolidating powdered materials into a collective structure due to, for example, bonding or irradiating the powdered materials, including by melting, bonding, fusing, joining, sintering, and the like.

[0061] The present disclosure generally relates to fabricating ceramic matrix composite (CMC) parts using additive manufacturing.

[0062] Manufacturing ceramic components generally involves aligning layers of fiber reinforcement material to be processed into the final product. The layer may be formed using a sheet of reinforcement material pre-impregnated with a ceramic material or pre-ceramic material. In addition, ceramic or pre-ceramic materials may be added additionally or alternatively during or after the alignment or layup process. However, due to the geometry of the original layup, the shape and size of the ceramic component may be limited, resulting in difficulties in achieving complex geometries of the ceramic component.

[0063] Additive manufacturing can be incorporated into CMC manufacturing, for example, for large hybrid CMC structures with additively manufactured cores laminated with CMC cover layers. Additive manufacturing allows green structures to be built layer by layer, potentially with more complex geometries, such as honeycomb patterns or parts with cooling channels and holes. After printing, the green structure can be cured or burned out to remove the binder material from the part. Subsequently, the part can be densified, such as by silicon infiltration, reactive bonding, chemical vapor infiltration, and other densification methods to reduce porosity in the part.

[0064] However, the raw material used for additive manufacturing of ceramic components (e.g., the core structure of such ceramic components) consists of monolithic ceramic raw material powders. For example, the raw material can use monolithic SiC, Si3N4, or mullite pellets. Although the raw material can provide the necessary chemical composition of the core, the large size of the monolithic particles will eventually lead to high porosity of the green body and high shrinkage of the component during the densification process. In addition, single material particles or pellets may lead to inefficient processing, such as reactive bonding by melt infiltration to produce a large amount of free silicon, thereby inhibiting the performance of the component at high temperatures.

[0065] Thus, the disclosure herein provides a new processing method for manufacturing ceramic components. Instead of using a monolithic feedstock to additively manufacture ceramic components, a new composite feedstock can be used, such as a reaction-bonded silicon carbide structure formed by reactive silicon melt infiltration, which contains silicon carbide and carbon particles, thereby providing a reactive pellet system. Pre-pelletizing of the combined particles enables the pellets to have a sufficient size to facilitate the additive manufacturing method, such as by being large enough to maintain good fluidity of the feedstock material. In addition, the formation of composite particles enables the customization of the chemical composition throughout the feedstock, which in turn can help adjust the properties of the ceramic component by customizing the composition and microstructure of the additively manufactured component (e.g., by reducing the amount of free silicon produced during the densification process).

[0066] Reference is now made to the drawings, wherein like numerals refer to like elements throughout. Figure 1 is a schematic cross-sectional view of a gas turbine engine according to an exemplary aspect of the present disclosure. More particularly, Figure 1 In an embodiment, the gas turbine engine is a high bypass ratio turbofan jet engine 10, referred to herein as a "turbofan engine 10". Figure 1 As shown, the turbofan engine 10 defines an axial direction A (extending parallel to the longitudinal centerline 12 for reference), a circumferential direction C (extending about the longitudinal centerline 12 and the axial direction A), and a radial direction R. Generally, the turbofan engine 10 includes a fan section 14 and a core turbine engine 16 disposed downstream of the fan section 14 .

[0067] The illustrated exemplary core turbine engine 16 generally includes a substantially tubular casing 18 defining an annular inlet 20. The casing 18 surrounds a compressor section in series flow relationship, the compressor section including a supercharger or low pressure (LP) compressor 22 and a high pressure (HP) compressor 24, a combustion section 26, a turbine section (including a high pressure (HP) turbine 28 and a low pressure (LP) turbine 30), and a jet exhaust nozzle section 32. A high pressure (HP) shaft or spool 34 drivingly connects the HP turbine 28 to the HP compressor 24. A low pressure (LP) shaft or spool 36 drivingly connects the LP turbine 30 to the LP compressor 22.

[0068] For the illustrated embodiment, fan section 14 includes a fan 38 having a plurality of fan blades 40 connected in a spaced-apart manner to a hub or disk 42. As shown, fan blades 40 generally extend outwardly from disk 42 in a radial direction R. Fan blades 40 and disk 42 together are rotatable about longitudinal centerline 12 via LP shaft or spool 36. In some embodiments, a power transmission having a plurality of gears may be included for reducing the rotational speed of LP shaft or spool 36 to a more efficient fan speed.

[0069] Still refer to Figure 1 In the exemplary embodiment of the present invention, the disk 42 is covered by a rotatable forward nacelle 48 having an aerodynamic shape to facilitate airflow through the plurality of fan blades 40. In addition, the exemplary fan section 14 includes an annular fan case or outer nacelle 50 that circumferentially surrounds the fan 38 and / or at least a portion of the core turbine engine 16. It should be understood that the fan case (nacelle) 50 can be configured to be supported relative to the core turbine engine 16 by a plurality of circumferentially spaced outlet guide vanes 52. In addition, the downstream section 54 of the fan case 50 can extend above the outer portion of the core turbine engine 16, thereby defining a bypass airflow passage 56 therebetween.

[0070] During operation of the turbofan engine 10, a volume of air 58 enters the turbofan engine 10 through the fan case 50 and / or the associated inlet 60 of the fan section 14. As the volume of air 58 passes through the fan blades 40, a first portion of the air 58, as indicated by arrow 62, is directed or routed into the bypass airflow passage 56, and a second portion of the air 58, as indicated by arrow 64, is directed or routed into the LP compressor 22. The ratio between the first portion of air 62 and the second portion of air 64 is generally referred to as a bypass ratio. The pressure of the second portion of air 64 is then increased as it passes through the compressor section and enters the combustion section 26, where it is mixed with fuel and combusted to provide combustion gases 66. More specifically, the compressor section includes the LP compressor 22 and the HP compressor 24, each of which may include a plurality of compressor stages 80, each of which includes an annular array or circumferential arrangement of stationary compressor blades 82 (also referred to as compressor stationary blades 82) and an annular array or circumferential arrangement of rotating compressor blades 84 (also referred to as compressor rotating blades 84) immediately adjacent to and downstream of the compressor blades 82. A plurality of compressor blades 84 in the LP compressor 22 are connected to the LP shaft or spool 36, and a plurality of compressor blades in the HP compressor 24 are connected to the HP shaft or spool 34. A plurality of compressor blades 82 in the LP compressor 22 are connected to a compressor casing, and a plurality of compressor blades 82 in the HP compressor 24 are connected to the compressor casing; at least a portion of the HP compressor blades 82 are connected to a compressor casing 90. In some embodiments, the compressor casing 90 may extend through the LP compressor 22 and the HP compressor 24 and support all of the compressor blades 82. In other embodiments, the compressor casing 90 supports only a portion of the compressor blades 82 and may support only a portion of the compressor blades 82 in the HP compressor 24. As previously described, as the second portion of air 64 passes through sequential stages of compressor blades 82 and compressor blades 84, the volume of the air 64 is pressurized, that is, the pressure of the air 64 is increased before being combusted with the fuel in the combustion section 26 to form the combustion gases 66.

[0071] The combustion gases 66 are directed through the HP turbine 28, wherein a portion of the heat and / or kinetic energy from the combustion gases 66 is extracted through sequential stages of HP turbine stationary blades 68 connected to the casing 18 and HP turbine rotating blades 70 connected to the HP shaft or spool 34, thereby rotating the HP shaft or spool 34 to support the operation of the HP compressor 24. The combustion gases 66 are then directed through the LP turbine 30, wherein a second portion of the heat and kinetic energy from the combustion gases 66 is extracted through sequential stages of LP turbine stationary blades 72 connected to the casing 18 and LP turbine rotating blades 74 connected to the LP shaft or spool 36, thereby rotating the LP shaft or spool 36 to support the operation of the LP compressor 22 and / or the rotation of the fan 38.

[0072] The combustion gases 66 are then directed through the jet exhaust nozzle section 32 of the core turbine engine 16 to provide propulsive thrust. At the same time, the pressure of the first portion of air 62 is greatly increased as it is directed through the bypass airflow passage 56 before being discharged from the fan nozzle exhaust section 76 of the turbofan engine 10, thereby also providing propulsive thrust. The HP turbine 28, the LP turbine 30, and the jet exhaust nozzle section 32 at least partially define a hot gas passage 78 for directing the combustion gases 66 through the core turbine engine 16.

[0073] although Figure 1 The gas turbine engine in the embodiment is shown in a turbine shaft configuration, but it should be understood that the teachings of the present disclosure can be applied to other types of turbine engines, more generally turbomachines, and other shaft systems. For example, the turbine engine can be another suitable type of gas turbine engine, such as a turboprop engine, a turbojet engine, a turbofan engine, an aero-derivative engine, etc. The present disclosure can also be applied to other types of turbomachinery, such as a steam turbine engine. In addition, the present disclosure can be applied to other types of composite components, such as composite components used in applications other than turbomachinery.

[0074] Figure 2 A-2E is a schematic diagram of different possible stages of producing a composite feedstock, such as a composite feedstock for additive manufacturing of a ceramic matrix composite (“CMC”) component, according to an example embodiment of the present disclosure. Figure 2 A-2E is intended to identify and describe pellets and powders and is not intended to represent actual physical shape or structure or relative proportions. Figure 2 A-2E depicts example process steps for purposes of illustration and discussion. One of ordinary skill in the art, using the disclosure provided herein, will appreciate that the methods described in this disclosure may be adjusted, modified, include steps not shown, omitted, and / or rearranged without departing from the scope of this disclosure.

[0075] exist Figure 2 In FIG. 1A , silicon carbide pellets 110 are shown as an exemplary starting material for SiC. The silicon carbide pellets can have a size, shape, and chemical properties suitable for additive manufacturing (e.g., for additive manufacturing of ceramic components including silicon carbide core structures). For example, the silicon carbide particles can have a sufficiently large size to be used as a powder material for layer-by-layer deposition during additive manufacturing (e.g., required fluidity). The silicon carbide pellets can also have a sufficiently small size to facilitate deposition, consolidation, reaction bonding, or a combination thereof during additive manufacturing.

[0076] In some examples, the particle size of the silicon carbide pellets 110 can be 20 μm to 80 μm, or 30 μm to 70 μm, or 40 μm to 60 μm, or about 50 μm, where the particle size refers to the maximum dimension across the pellet. A plurality of silicon carbide pellets 110 can be used together as a silicon carbide raw material for additive manufacturing. In the raw material, each silicon carbide pellet 110 may have some variations, such as having different sizes, shapes, or compositions. For example, the average particle size of the silicon carbide pellets 110 (i.e., the average value of the maximum dimensions of each pellet) may be within a wide or narrow range of different sizes. In some examples, the average particle size of the silicon carbide pellets 110 may be within a range of 20 μm to 80 μm, or within a range of 30 μm to 70 μm, or within a range of 40 μm to 60 μm, or the average particle size of the silicon carbide pellets 110 is about 50 μm.

[0077] The silicon carbide pellet 110 can be processed into a plurality of smaller silicon carbide particles. Processing the silicon carbide into small sizes enables subsequent customization and production of composite particles combining silicon carbide with one or more other materials. However, although Figure 2 A shows silicon carbide in pellet form, such as a collective raw material of a plurality of silicon carbide pellets, but the silicon carbide material may also be provided in other forms without departing from the scope of the present disclosure. In addition, the silicon carbide pellets 110 may contain a variety of other carbide phases, such as other transition metal carbides (e.g., B4C, VC, MoC, TiC or combinations thereof) and alloys thereof.

[0078] Figure 2 B shows a plurality of silicon carbide particles 120, for example, derived from Figure 2 The silicon carbide pellets 110 shown in A or silicon carbide particles of other methods. For example, the silicon carbide pellets 110 can be ground (e.g., ball milled) to form a plurality of silicon carbide particles 120 having a smaller average particle size. The grinding process can be performed using any suitable medium, as long as the medium does not change the chemical properties of the silicon carbide within the silicon carbide pellets 110 that form the silicon carbide particles 120. The silicon carbide particles 120 may include a plurality of particles containing silicon carbide. The size of the silicon carbide particles 120 may be smaller than the initial silicon carbide pellets 110. For example, the average particle size of the silicon carbide particles 120 may be 0.1 μm to 10 μm, or 0.5 μm to 5 μm, or about 1 μm; wherein the particle size refers to the maximum size across a single particle, and the average particle size refers to the average value of the maximum size of each particle. In addition, the plurality of silicon carbide particles 120 may all have the same particle size, or may vary within a certain size range.

[0079] Although Figure 22A and 2B show that a single silicon carbide pellet 110 is processed into a plurality of silicon carbide particles 120, but the individuality of the silicon carbide pellets 110 shown is only for convenience. That is, the plurality of silicon carbide pellets 110 may be collectively processed to produce a plurality of silicon carbide particles 120, wherein the size of the silicon carbide particles 120 is smaller than the initial silicon carbide pellets 110. Alternatively, a plurality of silicon carbide particles 120 may be directly provided without initial processing of the larger silicon carbide pellets 110.

[0080] As the larger silicon carbide pellets 110 are processed into smaller silicon carbide particles 120, the silicon carbide particles 120 may subsequently be combined with one or more additional elements (eg, additional particles having other compositions).

[0081] Figure 2 C shows a plurality of silicon carbide particles 120 combined with a plurality of carbon particles 130. The plurality of carbon particles 130 may include a plurality of particles including or consisting of carbon. In addition, the average particle size of the plurality of carbon particles 130 may be greater than, less than, or similar to the average particle size of the silicon carbide particles 120. For example, the particle size of the carbon particles 130 may be 0.1 μm to 10 μm, or 0.5 μm to 5 μm, or about 1 μm, wherein the particle size refers to the maximum size across a single particle, and the average particle size refers to the average of the maximum sizes of the individual particles. In addition, the plurality of carbon particles 130 may all have the same size, or may vary within a certain size range.

[0082] The silicon carbide particles 120 and the carbon particles 130 can be mixed using any suitable method to provide a uniform distribution of the different types of particles. After or during mixing, the silicon carbide particles 120 and the carbon particles 130 can form composite particles, such as by spray drying, pressing or other compaction methods.

[0083] Figure 2 A composite particle 140 is shown in D. The composite particle 140 includes a combination of one or more silicon carbide particles 120 and one or more carbon particles 130, which can be used for subsequent additive manufacturing and ultimately forming a ceramic component.

[0084] The composite particles 140 can be formed using any suitable method. For example, the composite particles 140 can include a binder 145 to help keep the silicon carbide particles 120 and the carbon particles 130 together in a granular form. For example, in some non-limiting embodiments, more than one aqueous or non-aqueous binder system can be used. Exemplary aqueous binder systems include, but are not limited to, polyvinyl alcohol (PVA), polymethyl methacrylate (PMMA), carboxymethyl cellulose (CMC), and similar compounds. Exemplary non-aqueous binder systems include, but are not limited to, high molecular weight.

[0085] In addition, one or more additional elements may be included in the composite particles 140. One or more additional elements may be included to facilitate subsequent additive manufacturing, formation of ceramic components, or a combination thereof. For example, in some examples, the composite particles 140 may include silicon.

[0086] Figure 2 E shows a plurality of composite particles 140 forming the composite raw material 200. The composite particles 140 may each include one or more silicon carbide particles 120 and carbon particles 130. In addition, the composite particles 140 may each include a binder.

[0087] By recombining smaller silicon carbide particles 120 and carbon particles 130 into composite particles 140, composite feedstock 200 can have a size and physical properties suitable for additive manufacturing while still combining silicon carbide and carbon materials. In addition, composite feedstock 200 can be customized based on the needs and desired properties of the ceramic part.

[0088] The composite feedstock 200 may include one or more additional materials, such as other refractory metals (e.g., B, Mo, W, V, and Ti) or transition metal carbides (e.g., BC, VC, MoC, TiC), either present in the one or more composite particles 140 themselves, or as separate pellets mixed with the composite particles. For example, in some examples, the composite feedstock 200 may include silicon, such as by adding silicon to the one or more composite particles 140.

[0089] The composite particles 140 and the overall composite feedstock 200 can be adjusted to provide a desired material distribution. For example, in some examples, the composite feedstock 200 may include 5 to 95 weight percent silicon carbide, 25 to 90 weight percent silicon carbide, or 40 to 80 weight percent silicon carbide based on solids. In some examples, the composite feedstock 200 may include 10 to 90 weight percent carbon, 20 to 60 weight percent carbon, or 30 to 50 weight percent carbon based on solids. In some examples, the balance of the solid particles may be provided by other metallic elements or carbide or boride compounds such as those described herein.

[0090] The composite particles 140 may have a shape and size that facilitates additive manufacturing. For example, the particle size of each composite particle 140 may be 20 μm to 80 μm, or 30 μm to 70 μm, or 40 μm to 60 μm, or about 50 μm, where the particle size refers to the largest dimension across the particle.

[0091] In the composite raw material, each composite particle 140 can have some variations, such as having different sizes, shapes, or compositions. For example, the average particle size of different composite particles 140 can be within a wide or narrow range of different sizes. In some examples, the average particle size of the composite particles 140 (referring to the average of the maximum size of each spherical particle) can be 20 μm to 80 μm, or 30 μm to 70 μm, or 40 μm to 60 μm, or about 50 μm.

[0092] The composite feedstock can then be used to additively manufacture a ceramic component or a portion of a ceramic component (e.g., a monolithic core). That is, additive manufacturing builds multiple consecutive layers of a ceramic component by selective consolidation of a composite feedstock (which includes silicon carbide and a carbon material). By using composite particles, the printed component can have a lower porosity, thereby reducing shrinkage in subsequent processing steps (e.g., curing). In addition, the customization of the chemical composition achieved by the composite feedstock is conducive to reducing net shrinkage through reactions between the components, as well as reducing free silicon during subsequent densification by melt infiltration using molten silicon.

[0093] Any suitable additive manufacturing method may be used. For example, in some examples, composite particles may be used to additively manufacture parts by binder jet printing (BJP), powder bed fusion (PBF), direct metal laser melting (DMLM) technology, selective laser melting (SLM) technology, direct metal laser sintering (DMLS) technology or selective laser sintering (SLS) technology, fused deposition modeling (FDM) technology, direct energy deposition (DED) technology, laser engineered net shape (LENS) technology, laser net shape manufacturing (LNSM) technology, digital light processing (DLP) technology.

[0094] After printing the initial part using the composite feedstock, the part can be subjected to one or more additional processing steps, such as resin or pre-ceramic polymer infusion and curing, followed by burnout to remove any binder, and densification by molten silicon infiltration. For example, parts produced by BJP and DLP additive manufacturing can be green bodies that include a binder. The green body can be subjected to a curing process, followed by a burnout step of the binder material to provide a part that is considered a porous part. The porous part can contain silicon carbide, carbon, and other components from the initial composite feedstock.

[0095] The porous component can then be densified to reduce its porosity. Densification can be achieved by infiltrating the pores with a densifying material (e.g., silicon, silicon-containing reactants, silicon alloys, or reactive vapor components of Si (e.g., SiO(g), SiH4, and SiCl4)). In some examples, densification can include melt infiltration (MI), wherein the component is infiltrated by molten silicon, so that the molten silicon is a densification fluid. In some examples, densification can include chemical vapor infiltration (CVI), wherein the component is infiltrated into a fiber preform using a reactive gas at high temperature to form a fiber reinforced composite material, so that the reactive gas is a densification fluid. In some examples, densification can include polymer infiltration and pyrolysis (PIP), wherein the component is infiltrated by a pre-ceramic polymer (e.g., polysilazane) and then heat treated to form a SiC matrix, so that the pre-ceramic polymer is a densification fluid. In some examples, densification can include oxide / oxide treatment (e.g., for aluminum or aluminosilicate reinforcement components). In some examples, densification can include a combination of these methods.

[0096] Figure 3 An exploded perspective view of an exemplary ceramic component 300 that can be produced using the methods and materials disclosed herein is shown. Figure 3 A particular configuration of the ceramic component 300 is depicted, but one of ordinary skill in the art, using the disclosure provided herein, will appreciate that alternative components or configurations may be adapted without departing from the scope of the present disclosure.

[0097] Figure 3 The ceramic component 300 shown in FIG. 1 generally includes a monolithic core 310 and one or more composite layers 320. The monolithic core 310 may be configured as a honeycomb structure including a plurality of walls 311 defining a plurality of hollow channels 312.

[0098] The monolithic core 310 can be additively manufactured using the composite feedstock disclosed herein. That is, the monolithic core 310 can be additively manufactured by selective consolidation of the composite feedstock to build up multiple continuous layers 315. Consolidation can include joining, sintering, bonding, or otherwise consolidating materials of the composite feedstock together by Si melt infiltration, reactive bonding, CVI, and PIP processes, or combinations thereof.

[0099] One or more composite layers 320 may include adjacent composite components, such as components having a similar composition to the monolithic core or having a different composition than the monolithic core. In some examples, the composite layers 320 may be laid on the surface of the monolithic core 310. Such examples provide for additive manufacturing of a complex monolithic core 310, also utilizing a less time-intensive layup process incorporating composite layers. In some examples, both the monolithic core 310 and the composite layers 320 may be additively manufactured as a single integral piece or as separate parts for subsequent joining. The composite layers 320 may then be joined to the monolithic core 310 to provide an integral ceramic component.

[0100] Figure 4 A flow chart of a method 400 of manufacturing a ceramic component according to an exemplary embodiment of the present disclosure is provided. Figure 4 Exemplary method steps are depicted for purposes of illustration and discussion. One of ordinary skill in the art, using the disclosure provided herein, will appreciate that the methods described in this disclosure may be adjusted, modified, include steps not shown, omitted, and / or rearranged without departing from the scope of this disclosure.

[0101] Method 400 may optionally include producing a composite feedstock in step 410. As disclosed herein, producing a granular feedstock may include combining a plurality of silicon carbide pellets with a plurality of carbon particles. One or more other materials may also be added, such as a binder, silicon, or both. Alternatively, the composite feedstock may be produced independently of the manufacture of the ceramic component.

[0102] The method 400 also includes additively manufacturing the ceramic component in step 420. As disclosed herein, additively manufacturing the ceramic component can include building a plurality of successive layers of the ceramic component by selective consolidation of a composite feedstock comprising a plurality of composite particles, wherein each of the plurality of composite particles comprises one or more silicon carbide particles and one or more carbon particles. Thus, the formed ceramic component can be substantially a monolithic component comprising the material of the composite feedstock substantially uniformly distributed therein. In alternative embodiments, the formed ceramic component can have a multiphase ceramic composition, such as a CMC.

[0103] Optionally, method 400 may further include laying up one or more composite layers onto the component additively manufactured in step 420 in step 425. For example, the component additively manufactured in step 420 may include a core onto which one or more CMC layers may be laid up in step 425. The core and layers may be joined to one another before, during, or after subsequent processing steps (e.g., densification).

[0104] The method 400 also includes densifying the component additively manufactured in step 420 in step 430. Densification can be achieved by silicon infiltration (e.g., by melt infiltration or chemical infiltration). In some embodiments, the component additively manufactured in step 420 can be subjected to a curing or burnout process to remove binder material prior to densification in step 430. Thus, the manufacturing method 400 can produce a ceramic component with reduced shrinkage during processing due to the composite feedstock, less free silicon from densification, and other potentially customizable properties.

[0105] The following clauses provide further aspects of the subject matter:

[0106] A method of manufacturing a ceramic matrix composite (CMC) component, the method comprising: building multiple consecutive layers of the ceramic component by selective consolidation of a composite feedstock comprising a plurality of composite particles, wherein each of the plurality of composite particles comprises one or more silicon carbide particles and one or more carbon particles; and densifying the CMC by silicon infiltration.

[0107] A method according to any of the preceding clauses, wherein each of the plurality of composite particles further comprises a binder.

[0108] A method according to any of the preceding clauses, wherein each of the plurality of composite particles further comprises silicon.

[0109] A method according to any of the preceding clauses, wherein the composite feedstock comprises 50 to 95 wt% silicon carbide.

[0110] A method according to any of the preceding clauses, wherein the composite feedstock comprises 5 to 50 wt% carbon.

[0111] A method according to any of the preceding clauses, wherein the composite feedstock comprises 5 to 35 wt% silicon.

[0112] A method according to any of the preceding clauses, wherein the average particle size of the plurality of composite particles of the composite feedstock is from 5 μm to 75 μm.

[0113] A method according to any of the preceding clauses, wherein the method further comprises combining a plurality of silicon carbide particles with a plurality of carbon particles to form a plurality of composite particles.

[0114] The method according to any of the preceding clauses, wherein the plurality of silicon carbide particles have an average particle size of 0.1 μm to 10 μm.

[0115] The method according to any of the preceding clauses, wherein the average particle size of the plurality of carbon particles is from 0.1 μm to 10 μm.

[0116] A method according to any of the preceding clauses, wherein building up the plurality of successive layers of the ceramic component comprises curing the composite feedstock by binder jet printing or digital light processing.

[0117] A method according to any of the preceding clauses, wherein densifying the ceramic component comprises melt infiltration or chemical vapor infiltration using molten silicon.

[0118] A method according to any of the preceding clauses, wherein the method further comprises laying up one or more composite layers on the CMC component, and joining the one or more composite layers to form the CMC component.

[0119] Method according to any of the preceding clauses, wherein the ceramic component is a turbine component or a structural component or an aerodynamic component designed for use as a component of a high temperature propulsion and / or hot gas flow trajectory control system.

[0120] A method of making a ceramic matrix composite (CMC) component, the method comprising: building a plurality of successive layers of the CMC component by selective consolidation of a composite feedstock, wherein the composite feedstock comprises a plurality of composite particles formed by a combination of one or more silicon carbide particles and one or more carbon particles, the composite feedstock comprising 5 to 95 weight percent silicon carbide and 5 to 40 weight percent carbon; and densifying the CMC component by infiltration using silicon or a silicon-containing reactant.

[0121] A method according to any of the preceding clauses, wherein the method further comprises: combining a plurality of silicon carbide particles having an average particle size of 0.1 μm to 10 μm with a plurality of carbon particles having an average particle size of 0.1 μm to 10 μm to form a plurality of composite particles.

[0122] A method according to any of the preceding clauses, wherein the composite feedstock further comprises 5 to 35 wt% silicon.

[0123] A method according to any of the preceding clauses, wherein the average particle size of the plurality of composite particles of the composite feedstock is from 5 μm to 75 μm.

[0124] A composite raw material comprises a plurality of composite particles, each of the plurality of composite particles comprises one or more silicon carbide particles and one or more carbon particles; the composite raw material comprises 5 to 95 wt % of silicon carbide and 5 to 40 wt % of carbon; and the average particle size of the plurality of composite particles of the composite raw material is 5 μm to 75 μm.

[0125] A composite feedstock as in any preceding clause, wherein one or more of the plurality of composite particles further comprises a binder.

[0126] A composite feedstock as in any preceding clause, wherein one or more of the plurality of composite particles further comprises silicon.

[0127] This written description uses examples to disclose the present disclosure, including the best mode, and also to enable any person skilled in the art to practice the present disclosure, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the present disclosure is defined by the claims, and may include other examples that occur to one skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.

Claims

1. A method for manufacturing a ceramic matrix composite (CMC) component, the method comprising: Building a plurality of successive layers of the CMC component by selective consolidation of a composite feedstock comprising a plurality of composite particles, wherein each of the plurality of composite particles comprises one or more silicon carbide particles and one or more carbon particles; and Densification of CMC parts by silicon infiltration.

2. The method according to claim 1, wherein: Each of the plurality of composite particles further comprises a binder.

3. The method according to claim 2, wherein: Each of the plurality of composite particles further comprises silicon.

4. The method according to claim 1, wherein: The composite feedstock contains 50 to 95% by weight of silicon carbide.

5. The method according to claim 4, wherein: The composite feedstock contains 5 to 50 wt % carbon.

6. The method according to claim 5, wherein: The composite raw material contains 5 to 35% by weight of silicon.

7. The method according to claim 1, wherein: The average particle size of the plurality of composite particles of the composite raw material is 5 μm to 75 μm.

8. The method according to claim 1, wherein: The method also includes combining the plurality of silicon carbide particles with the plurality of carbon particles to form a plurality of composite particles.

9. The method according to claim 8, wherein: The plurality of silicon carbide particles have an average particle size of 0.1 μm to 10 μm.

10. The method according to claim 9, wherein: The carbon particles have an average particle size of 0.1 μm to 10 μm.

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