A method may include depositing a sacrificial support material on or adjacent to a build surface. The sacrificial support material may be configured to support a continuous reinforcement material during an additive manufacturing technique. The method also may include extruding the continuous reinforcement material from an additive manufacturing device such that at least a portion of the continuous reinforcement material contacts and is supported by the sacrificial support material; and removing the sacrificial support material to result in a feature defined at least in part by the continuous reinforcement material at the absence of sacrificial support material.

Disclosed is a modified preceramic polymer having a polymer backbone consisting of silicon or a combination of silicon and carbon; and a pendant modifier bonded to the backbone wherein the modifier includes silicon, boron, aluminum, a transition metal, a refractory metal, or a combination thereof. The modified preceramic polymer can be used to form a ceramic matrix composite.

A method is provided for growing a fiber structure, where the method includes: obtaining a substrate, growing an array of pedestal fibers on the substrate, growing fibers on the pedestal fibers, and depositing a coating surrounding each of the fibers. In another aspect, a method of fabricating a fiber structure includes obtaining a substrate and growing a plurality of fibers on the substrate according to 1½D printing. In another aspect, a multilayer functional fiber is provided produced by, for instance, the above-noted methods.

A ceramic matrix composite includes at least one ply of ceramic fibers and a a ceramic matrix material deposited on the ceramic fibers. A fiber volume fraction is between about 35-45% and an areal weight fibers is between about 150-450 g/m2. A method of fabricating a ceramic matrix composite component is also disclosed.

A system and method for forming a porous ceramic preform is provided. The method may include forming a stacked powder structure including a binder layer and a powder layer on the binder layer. The binder layer may be formed by depositing a binder with a spray nozzle on a substrate. The powder layer may be formed by depositing a powder on the binder layer. The porous ceramic preform may be formed by heating the stacked powder structure to pyrolyze the binder. The porous ceramic preform is configured to be infiltrated by a molten material. The substrate may comprise a ceramic fiber preform. After melt infiltration of the porous ceramic preform and the ceramic fiber preform, a densified ceramic feature having a predetermined geometry may be formed on a ceramic matrix composite (CMC) component.

A method to form a machinable ceramic matrix composite comprises forming a porous ceramic multilayer on a surface of a fiber preform. In one example, the porous ceramic multilayer comprises a gradient in porosity in a direction normal to the surface. In another example, the porous ceramic multilayer includes low-wettability particles having a high contact angle with molten silicon, where an amount of the low-wettability particles in the porous ceramic multilayer varies in a direction normal to the surface. After forming the porous ceramic multilayer, the fiber preform is infiltrated with a melt, and the melt is cooled to form a ceramic matrix composite with a surface coating thereon. An outer portion of the surface coating is more readily machinable than an inner portion of the surface coating. The outer portion of the surface coating is machined to form a ceramic matrix composite having a machined surface with a predetermined surface finish and/or dimensional tolerance.

Disclosed herein is a ceramic matrix composite airfoil comprising a triple bifurcated ply that defines a suction side, an outer platform, a pressure side and an inner platform of the airfoil, wherein the triple bifurcated ply comprises at least one ply that comprises a consolidated region, wherein the consolidated region is split into two bifurcated regions in three locations in three different directions.

A method for producing a consolidated fiber preform intended for the manufacture of a part made of composite material, includes shaping a fiber texture in a heated metal mold, the texture being pre-impregnated with a transient or fugitive material, or shaping a fiber texture in a metal mold and injecting a transient or fugitive material into the fiber texture held in shape in the metal mold, cooling the mold, removing the set fiber preform from the mold, coating the fiber preform with a slurry containing a powder of ceramic or carbon particles, heat-treating the coated fiber preform so as to form a porous shell around the fiber preform by consolidation of the slurry and so as to remove the transient or fugitive material present in the fiber preform, consolidating the fiber preform by gas-phase chemical infiltration.

A method of making a ceramic matrix composite (CMC) that may show improved resistance to chemical attack from molten silicon along with excellent mechanical strength is described. The method includes forming an interphase coating on one or more silicon carbide fibers, depositing a matrix layer comprising silicon carbide on the interphase coating, oxidizing the matrix layer to form an oxidized film comprising silicon oxide, depositing a wetting layer comprising silicon carbide on the oxidized film. After depositing the wetting layer, a fiber preform containing the silicon carbide fibers is heat treated. After the heat treatment, the fiber preform is infiltrated with a slurry. After infiltration with the slurry, the fiber preform is infiltrated with a melt containing silicon, and then the melt is cooled to form a ceramic matrix composite.

Composite materials that include a plurality of nanofibers and a ceramic. Methods of forming composite materials, which may include removing a liquid from a dispersion that includes a plurality of nanofibers, a pre-ceramic precursor, and a liquid to form an intermediate material, and annealing the intermediate material. A pre-ceramic precursor may be added before or after removal of a liquid. An article having a surface on which a composite material is disposed.