A method of fabricating a composite part, includes forming a fiber preform for the part that is to be obtained by depositing a plurality of fiber structures impregnated with a thermoplastic polymer onto a surface, with deposition being performed by automated fiber placement; eliminating the thermoplastic polymer present in the preform by dissolution with a solvent; and injecting a liquid impregnation composition into the pores of the fiber preform after eliminating the thermoplastic polymer in order to form a matrix in the pores of the fiber preform.

A composite article is comprised of coal dust, as defined herein, and a polymer derived ceramic material that is pyrolyzed in a substantially non-oxidizing atmosphere. For example, the composite article may be made of a mixture of the coal dust and polymer derived ceramic, from particles formed of a mixture of coal dust and polymer derived ceramic or from complex particle composites comprising a plurality of particles formed of a mixture of coal dust and polymer derived ceramic.

The present disclosure includes a system and method for monitoring degradation of a high temperature composite component (HTC). The HTC is defined by a volume that includes a matrix material and a fiber formed from at least one of ceramic and carbon material. One or more electrical conductors are disposed within the volume and connected directly or indirectly to a monitoring system.

Methods of forming solid carbon products include disposing a plurality of nanotubes in a press, and applying heat to the plurality of carbon nanotubes to form the solid carbon product. Further processing may include sintering the solid carbon product to form a plurality of covalently bonded carbon nanotubes. The solid carbon product includes a plurality of voids between the carbon nanotubes having a median minimum dimension of less than about 100 nm. Some methods include compressing a material comprising carbon nanotubes, heating the compressed material in a non-reactive environment to form covalent bonds between adjacent carbon nanotubes to form a sintered solid carbon product, and cooling the sintered solid carbon product to a temperature at which carbon of the carbon nanotubes do not oxidize prior to removing the resulting solid carbon product for further processing, shipping, or use.

Methods and apparatuses for additive manufacturing are described. A method for additive manufacturing may include exposing a layer of material on a build surface to one or more projections of laser energy including at least one line laser having a substantially linear shape. The intensity of the line laser may be modulated so as to cause fusion of the layer of material according to a desired pattern as the one or more projections of laser energy are scanned across the build surface.

There is provided a fiber-reinforced brittle matrix composite. The fiber-reinforced brittle matrix composite comprises a brittle matrix material (for example, a cementitious or ceramics material) and a coated fiber embedded in the brittle matrix material, wherein the coated fiber comprises a fiber (for example, polyethylene fiber, glass fiber, silicon carbide fiber, alumina fiber, mullite fiber) and a coating material (for example, carbon nanofibers, carbon nanotubes), which is non-covalently disposed on the fiber. A method for producing the fiber-reinforced brittle matrix composite is also provided. The method comprises providing a fiber, disposing a coating material on the fiber to form a coated fiber, wherein the coating material is non-covalently disposed on the fiber, and embedding the coated fiber in a brittle matrix material to obtain the fiber-reinforced brittle matrix composite.

Provided herein are methods of making composite materials. The methods may include infiltrating a carbon nanoscale fiber network with a ceramic precursor, curing the ceramic precursor, and/or pyrolyzing the ceramic precursor. The infiltrating, curing, and pyrolyzing steps may be repeated one or more times. Composite materials also are provided that include a ceramic material and carbon nanoscale fibers.

A method of making a ceramic composite component includes providing a fibrous preform or a plurality of fibers, providing a first plurality of particles, coating the first plurality of particles with a coating to produce a first plurality of coated particles, delivering the first plurality of coated particles to the fibrous preform or to an outer surface of the plurality of fibers, and converting the first plurality of coated particles into refractory compounds. The first plurality of particles or the coating comprises a refractory metal.

A method of treating a carbon/carbon composite is provided. The method may include infiltrating a carbonized fibrous structure with hydrocarbon gas to form a densified fibrous structure. The method may include treating the densified fibrous structure with heat at a first temperature range from about 1600 to about 2400 C. to form a heat treated densified fibrous structure. The method may include infiltrating the heat treated densified fibrous structure with silicon to form a silicon carbide infiltrated fibrous structure.

A method of manufacturing nuclear fuel elements may include: forming a base portion of the fuel element by depositing a powdered matrix material including a mixture of a graphite material and a fibrous material; depositing particles on the base portion in a predetermined pattern to form a first particle layer, by controlling the position of each particle in the first particle layer; depositing the matrix material on the first particle layer to form a first matrix layer; depositing particles on the first matrix layer in a predetermined pattern to form a second particle layer by controlling positions of each particle in the second particle layer; depositing the matrix material on the second particle layer to form a second matrix layer; and forming a cap portion of the fuel pebble by depositing the matrix material. The particles in the first particle layer and the second particle layer include nuclear fuel particles.