Abstract: A method that includes winding a composite fabric around a mandrel to form a plurality of layers defining an annulus extending along a central longitudinal axis, where the composite fabric includes a plurality of elongate axial fibers extending substantially in an axial direction relative to the longitudinal axis and a plurality of elongate circumferential fibers extending substantially in a circumferential direction relative to the longitudinal axis; and introducing, into at least a portion of the plurality of layers, a plurality of radial fibers extending substantially in the radial direction relative to the longitudinal axis, where the plurality of radial fibers mechanically bind one or more adjacent layers of the plurality of layers.

Abstract: A method that includes winding a composite fabric around a mandrel to form a plurality of layers defining an annulus extending along a central longitudinal axis, where the composite fabric includes a plurality of elongate axial fibers extending substantially in an axial direction relative to the longitudinal axis and a plurality of elongate circumferential fibers extending substantially in a circumferential direction relative to the longitudinal axis; and introducing, into at least a portion of the plurality of layers, a plurality of radial fibers extending substantially in the radial direction relative to the longitudinal axis, where the plurality of radial fibers mechanically bind one or more adjacent layers of the plurality of layers.

Abstract: A preform for a carbon-carbon composite including a plurality of fibrous layers stacked and needled-punched together to form the preform in the shape of an annulus having an inner radial section and an outer radial section. Each fibrous layer includes a respective plurality of fabric segments comprising at least one of carbon fibers or carbon-precursor fibers. At least one fibrous layer includes a first fabric segment forming at least a portion the inner radial section, the first fabric segment defining a first segment bisector and a first fiber orientation angle, and a second fabric segment forming at least a portion the outer radial section, the second fabric segment defining a second segment bisector and a second fiber orientation angle, where the first and second segment bisectors are radially aligned and the first fiber orientation angle is different than the second fiber orientation angle.

Abstract: A preform for a carbon-carbon composite including a plurality of fibrous layers superposed and needled-punched together. Each fibrous layer of the plurality of fibrous layers includes web fibers and tow fibers that each include at least one of carbon fibers or carbon-precursor fibers. The plurality of fibrous layers includes a first, a second, and a third fibrous layer, the third fibrous layer positioned between the first and the second fibrous layers. The third fibrous layer includes at least one of a ratio of web fibers to tow fibers that is less than a ratio of web fibers to tow fibers of the first fibrous layer, an areal weight that is greater than an areal weight of the first fibrous layer, or a pre-needled thickness that is greater than a pre-needled thickness the first fibrous layer.

Abstract: A preform for a carbon-carbon composite including a plurality of fibrous layers stacked and needled-punched together to form the preform in the shape of an annulus having an inner radial section and an outer radial section. Each fibrous layer includes a respective plurality of fabric segments comprising at least one of carbon fibers or carbon-precursor fibers. At least one fibrous layer includes a first fabric segment forming at least a portion the inner radial section, the first fabric segment defining a first segment bisector and a first fiber orientation angle, and a second fabric segment forming at least a portion the outer radial section, the second fabric segment defining a second segment bisector and a second fiber orientation angle, where the first and second segment bisectors are radially aligned and the first fiber orientation angle is different than the second fiber orientation angle.

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 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: 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 including depositing a resin and a plurality of carbon fibers 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 the resin and carbon fibers, and wherein the carbon fiber preform exhibits at least one of a non-uniform composition of the resin within the preform, different types of the carbon fibers within the preform, or non-uniform fiber orientation within the preform.

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: The disclosure describes a method of forming a carbon-carbon composite component including depositing an initial carbon material into a porous preform using chemical vapor deposition (CND) or chemical vapor infiltration (CVI) to form a rigidized porous preform, infusing the rigidized porous preform with an isotropic resin, pyrolyzing the infused isotropic resin to form an isotropic carbon within pores of the rigidized porous preform, and encapsulating the isotropic carbon, with a graphitizable carbon to form the carbon-carbon composite component.

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: In some examples, the disclosure describes a method including depositing a first layer including a resin and at least one of a carbon fiber or a carbon fiber precursor material on a work surface of a three-dimensional printing system, carbonizing at least the resin of the first layer using a carbonizer attached to the three-dimensional printer to form a first layer of carbon-carbon composite including carbon fibers and carbonized matrix material, depositing an additional layer including a resin and at least one of a carbon fiber or a carbon fiber precursor material of material on the first layer of carbon-carbon composite, and carbonizing at least the resin of the additional layer using the carbonizer to form an additional layer of carbon-carbon composite on the first layer of carbon-carbon composite.

Abstract: A technique of forming a carbon-carbon composite that includes infiltrating a preform comprising carbon fibers or carbon-precursor fibers with a pitch and pyrolyzing the pitch using a controlled pressure and temperature ramp rate to control a growth of optical textures as the pitch is pyrolyzed to a coke matrix. Pyrolyzing the pitch may include initiating pyrolysis of at least some of the pitch at a first pressure less than about 2000 psi and a first temperature ramp rate between about 5° C./hr and about 50° C./hr to a first target temperature, and pyrolyzing at least some of the pitch at a second pressure greater than 2000 psi and a second temperature ramp rate between about 5° C./hr and about 50° C./hr to a second target temperature, where the second target temperature is greater than the first target temperature.

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 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 technique of forming a carbon-carbon composite that includes infiltrating a preform comprising carbon fibers or carbon-precursor fibers with a pitch and pyrolyzing the pitch using a controlled pressure and temperature ramp rate to control a growth of optical textures as the pitch is pyrolyzed to a coke matrix. Pyrolyzing the pitch may include initiating pyrolysis of at least some of the pitch at a first pressure less than about 2000 psi and a first temperature ramp rate between about 5 ° C./hr and about 50 ° C./hr to a first target temperature, and pyrolyzing at least some of the pitch at a second pressure greater than 2000 psi and a second temperature ramp rate between about 5 ° C./hr and about 50 ° C./hr to a second target temperature, where the second target temperature is greater than the first target temperature.

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: In some examples, a method including depositing a resin and a plurality of carbon fibers 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 the resin and carbon fibers, and wherein the carbon fiber preform exhibits at least one of a non-uniform composition of the resin within the preform, different types of the carbon fibers within the preform, or non-uniform fiber orientation within the preform.

Abstract: In some examples, the disclosure describes a method including depositing a first layer including a resin and at least one of a carbon fiber or a carbon fiber precursor material on a work surface of a three-dimensional printing system, carbonizing at least the resin of the first layer using a carbonizer attached to the three-dimensional printer to form a first layer of carbon-carbon composite including carbon fibers and carbonized matrix material, depositing an additional layer including a resin and at least one of a carbon fiber or a carbon fiber precursor material of material on the first layer of carbon-carbon composite, and carbonizing at least the resin of the additional layer using the carbonizer to form an additional layer of carbon-carbon composite on the first layer of carbon-carbon composite.