Abstract: A carbon fiber preform that includes a plurality of fibrous layers stacked together and a plurality of sacrificial fibers that bind the plurality of fibrous layers together, where at least one fibrous layer of the plurality of fibrous layers includes a plurality of carbon fibers or carbon fiber precursor fibers.

Abstract: A technique of forming a carbon-carbon composite material includes infusing a liquid carbonizable precursor into a porous preform, and the infused precursor is subsequently pyrolyzed to convert the precursor to isotropic carbon. The preform then can be densified with a densifying agent, followed by infusion of the liquid carbonizable precursor into the densified preform. In some examples, after pyrolyzing the liquid carbonizable precursor, isotropic carbon extends substantially throughout a volume of the carbon-carbon composite material.

Abstract: In some examples, a method includes depositing a mixture including a resin and an additive powder via a print head of a three-dimensional printing system to form a carbon fiber preform including a plurality of individual carbon fiber layers, wherein each individual layer of the plurality of individual carbon fiber layers includes a plurality of carbon fibers and the mixture of the resin and the additive powder.

Abstract: A method for making a carbon-carbon composite brake disc by infiltrating a porous carbon preform with a resin and carbonizing the resin-infiltrated preform at a high pressure of at least about 5,000 psi to form a densified carbon-carbon composite disc brake with a final density of at least about 1.9 g/cc. The porous carbon preform includes a plurality of fabric sheets having non-woven oxidized polyacrylonitrile fibers, pitch fibers, or rayon fibers and a basis weight in the range from about 1250 to about 3000 grams per square meter. The fabric sheets are needled together. The porous carbon preform is infiltrated with resin, which includes at least one of an isotropic resin or a mesophase resin.

Abstract: In some examples, the disclosure describes a method including densifying a layer of carbon fibers by at least one of depositing a resin on the layer of carbon fibers via a print head of a three-dimensional printing system or applying CVD on the layer of carbon fibers via the print head; and forming at least one additional layer of densified carbon fibers on the densified layer of carbon fibers, wherein forming the at least one additional layer of densified carbon fibers comprises, for each respective layer of the at least one additional layer, adding an additional layer of carbon fibers on the densified layer of carbon fibers, and densifying the additional layer of carbon fibers by at least one of depositing the resin on the additional layer of carbon fibers or applying CVD on the additional layer of carbon fibers. In some examples, the example method may be used to form a densified carbon-carbon composite component, such as, e.g., a densified carbon-carbon composite brake disc.

Abstract: In one example, a method including depositing an antioxidant material on a first surface region of a carbon-carbon composite substrate via a print head of a three-dimensional printing device to form a first layer of the antioxidant material on the first surface region of the substrate, and depositing the antioxidant material on a second surface region of the substrate via the print head of the three-dimensional printing device to form a second layer of the antioxidant material on the second surface region. The method may be, for example, a method for forming a carbon-carbon composite component including an antioxidant coating, the antioxidant coating including the first layer and second layer of the antioxidant material.

Abstract: In some examples, a method for forming a carbon fiber preform comprises depositing a composite material on a substrate to form a first layer of the composite material, wherein the composite material comprises a carbon reinforcement material mixed in a resin matrix material; and depositing the composite material on the first layer to form a second layer on the first layer, wherein the carbon fiber preform includes the first layer of the composite material and the second layer of composite material, and includes the carbon reinforcement material and the resin matrix material.

Abstract: In some examples, a method for forming a carbon fiber preform comprises depositing, via a print head of a three-dimensional printing system, a first plurality of coated carbon fibers on a substrate to form a first layer on the substrate, wherein each carbon fiber of the first plurality of coated carbon fibers comprises a carbon fiber coated with a resin; and depositing, via the print head of the three-dimensional printing system, a second plurality of coated carbon fibers on the first layer to form a second layer on the first layer, wherein each carbon fiber of the second plurality of coated carbon fibers comprises the carbon fiber coated with the resin, and wherein the carbon fiber preform includes the first layer of the first plurality of coated carbon fibers and the second layer of the second plurality of coated carbon fibers.

Abstract: In some examples, a method for forming a carbon fiber preform includes depositing, via a print head of a three-dimensional printing system, a first plurality of carbon fibers to form a first layer of carbon fibers in approximately an x-y plane, wherein the first plurality of carbon fibers are deposited around an array of carbon fiber filaments extending in approximately a z-axis direction relative to the x-y plane.

Abstract: A method of forming a densified preform or composite part is disclosed that includes partially densifying a porous preform, forming channels in the partially densified preform that open to an exterior surface of the partially densified preform, infiltrating a densifying agent, such as pitch, into at least some of the channels of the partially densified preform, at least partially stabilizing the densifying agent, including heating at a first temperature, such that cracks form within the densifying agent, and exposing the preform to an oxidizing agent, and heating the at least partially stabilized preform at a second temperature to carbonize at least the stabilized densifying agent. A partially densified preform including a densifying agent disposed at least in such channels also is disclosed.

Abstract: A technique of heating a mixture of fibers that includes sacrificial fibers and carbon fiber precursor fibers to a temperature between about 170° C. and about 400° C., such that the sacrificial fibers are substantially removed and a plurality of channels remain in a preform precursor, and carbonizing the carbon fiber precursor fibers to form a porous carbon fiber preform. Also disclosed is a technique of heating a mixture of fibers that includes sacrificial fibers and carbon fibers to a temperature between about 170° C. and about 400° C., such that the sacrificial fibers are substantially removed and a plurality of channels remain, and infiltrating a densifying agent into at least the plurality of channels. Also disclosed is an article including a mixture of fibers that includes sacrificial fibers and carbon fiber precursor fibers or carbon fibers.

Abstract: In one example, a method includes mixing a plurality of carbon fibers in a liquid carrier to form a mixture, depositing the carbon fiber mixture in a layer, forming a plurality of corrugations in the carbon fiber layer, and rigidifying the corrugated carbon fiber layer to form a corrugated carbon fiber preform. In another example, a method includes substantially aligning a first ridge on a first surface of a first corrugated carbon fiber preform and a first groove on a first surface of a second corrugated carbon fiber preform, bringing the first surface of the first corrugated carbon fiber preform into contact with the first surface of the second corrugated carbon fiber preform, and densifying the first corrugated carbon fiber preform and the second carbon fiber preform to bond the first corrugated carbon fiber preform and the second carbon fiber preform.

Abstract: In the manufacture of carbon-carbon composite brake discs, migration of anti-oxidant substances into the friction surfaces is prevented by limiting or eliminating surface porosity in the carbon-carbon composite brake materials. The method includes infusing a suitable resin into pores in surface layers of the carbon-carbon composite disc and then charring the resin-infused disc to convert the resin in the pores to pyrolytic carbon. The resin may be infused into the carbon disc by submerging the disc in a molten resin. Prior to submerging the disc in the molten resin, the disc may subjected to a vacuum to remove air from the pores. While the disc is submerged in the molten resin, the pressure in the pressurizable vessel may increased to force the molten resin into the open porosity of the disc.

Abstract: A technique of forming a carbon-carbon composite material includes infusing a liquid carbonizable precursor into a porous preform, and the infused precursor is subsequently pyrolyzed to convert the precursor to isotropic carbon. The preform then can be densified with a densifying agent, followed by infusion of the liquid carbonizable precursor into the densified preform. In some examples, after pyrolyzing the liquid carbonizable precursor, isotropic carbon extends substantially throughout a volume of the carbon-carbon composite material.

Abstract: Methods of making a carbon-carbon composite preforms, particularly suitable as brake discs in aircraft landing systems, by combining titanium carbide particles ranging in size from 0.01 to 10 microns in diameter, resinous binder, and carbon fibers or carbon fiber precursors in a mold, and subsequently subjecting the combined components to pressure and heat to carbonize the resinous binder by methods, thereby providing the carbon-carbon composite preform having particulate titanium carbide uniformly distributed throughout its mass. Prior to combining the titanium carbide and the binder with the fibers in this process, the particulate titanium carbide may be mixed with liquid binder, the resulting TiC/binder mixture may then solidified, and the resulting solid TiC/binder mixture may be ground into a fine powder for use in the process. Also, compositions for preparing a carbon-carbon composite friction materials, and methods of improving wear and dynamic stability in a carbon-carbon composite brake discs.

Abstract: In one example, a method includes mixing a plurality of carbon fibers in a liquid carrier to form a mixture, depositing the carbon fiber mixture in a layer, forming a plurality of corrugations in the carbon fiber layer, and rigidifying the corrugated carbon fiber layer to form a corrugated carbon fiber preform. In another example, a method includes substantially aligning a first ridge on a first surface of a first corrugated carbon fiber preform and a first groove on a first surface of a second corrugated carbon fiber preform, bringing the first surface of the first corrugated carbon fiber preform into contact with the first surface of the second corrugated carbon fiber preform, and densifying the first corrugated carbon fiber preform and the second carbon fiber preform to bond the first corrugated carbon fiber preform and the second carbon fiber preform.

Abstract: An apparatus for bonding a first carbon composite to a second carbon composite through a reactant layer includes a housing, and a pair of conductive press plates electrically isolated from the housing. The press plates are adapted to position the two parts to be bonded with a reactant layer therebetween. The press plates are subjected to an electrical potential and a clamping force, sufficient to initiate a combustion reaction that creates a molten ceramic to bond together the carbon-carbon composites.

Abstract: A brake disk (10) includes an annular core (12, 60, 82) formed from a plurality of non-annular pieces (40, 66, 68, 84), a first friction disk (14) mounted on a first side of the annular core (12, 60, 82), a second friction disk (14) mounted on a second side of the core (12, 60, 82) opposite from the first friction disk (14), and at least one fastener (58) connecting the first and second friction disks (14, 14) to the core (12, 60, 82). Also a method of assembling a brake disk from a core and friction elements.

Abstract: A method of manufacturing a carbon-carbon brake disc uses a restraint fixture (12) that includes a preform retention region configured to limit contracting forces applied against a preform (10) in the preform retention region when the restraint fixture (12) thermally contracts. In one embodiment, the restraint fixture (12) comprises a band (12) having a first surface defining the preform retention region and a first expansion portion (26, 28, 29) adapted to deform upon application of a force to the band (12).

Abstract: Methods of making a carbon-carbon composite preforms, particularly suitable as brake discs in aircraft landing systems, by combining titanium carbide particles ranging in size from 0.01 to 10 microns in diameter, resinous binder, and carbon fibers or carbon fiber precursors in a mold, and subsequently subjecting the combined components to pressure and heat to carbonize the resinous binder by methods, thereby providing the carbon-carbon composite preform having particulate titanium carbide uniformly distributed throughout its mass. Prior to combining the titanium carbide and the binder with the fibers in this process, the particulate titanium carbide may be mixed with liquid binder, the resulting TiC/binder mixture may then solidified, and the resulting solid TiC/binder mixture may be ground into a fine powder for use in the process. Also, compositions for preparing a carbon-carbon composite friction materials, and methods of improving wear and dynamic stability in a carbon-carbon composite brake discs.