Abstract: An example technique includes extruding, by a tow deposition device, on a tow-by-tow basis, respective impregnated tows of a plurality of respective impregnated tows to form a layer of material on a major surface of a substrate. Each respective impregnated tow includes at least one ceramic fiber and a curable resin coating the at least one ceramic fiber. The example technique includes curing the curable resin to form a cured composite component. An example system includes a tow deposition device, an energy source, and a computing device. The computing device is configured to control the tow deposition device to extrude, on a tow-by-tow basis, respective impregnated tows of a plurality of respective impregnated tows to form a layer of material, and is configured to control the energy source to cure the curable resin to form a cured composite component.

Abstract: A turbine vane comprising ceramic matrix composite materials includes a vane support core, an airfoil, and an end wall that at least partially defines a gas path. The turbine vane is formed from a plurality of ceramic plies or preforms that are infiltrated with ceramic matrix material to form a one-piece ceramic matrix composite turbine vane.

Abstract: A method comprises inspecting a ceramic matrix composite component assembled in a gas turbine engine to determine an extent of damage to the ceramic matrix composite component, determining a repair technique to repair the damage to the ceramic matrix composite component based on the extent of damage to the ceramic matrix composite component, and repairing the ceramic matrix composite component using the repair technique.

Abstract: A method of infiltrating a fiber preform comprises positioning an assembly in a process chamber, where the assembly includes a tool comprising through-holes, a fiber preform constrained within the tool, and a sacrificial preform disposed between the fiber preform and the tool. The sacrificial preform is gas permeable. The process chamber is heated, and gaseous reactants are delivered into the process chamber during the heating. The gaseous reactants penetrate the through-holes of the tool and infiltrate the sacrificial preform and the fiber preform. Deposition of reaction products occurs on exposed surfaces of the fiber preform and the sacrificial preform, and a coating is formed thereon. In addition, the sacrificial preform accumulates excess coating material formed from increased reactions at short diffusion depths. Accordingly, the coating formed on the fiber preform exhibits a thickness variation of about 10% or less throughout a volume of the fiber preform.

Abstract: A method of making a ceramic fiber tow and the system regarding the same may be included. The method may include commingling a plurality of ceramic fibers with a fugitive fiber to form a single ceramic fiber tow. The fugitive fiber may be positioned between at least two ceramic fibers included in the single ceramic fiber tow. The method may further include forming a porous ceramic preform including at least the single ceramic fiber tow. The method may further include removing the fugitive fiber from the ceramic fiber tow leaving a space between at least two ceramic fibers of the single ceramic fiber tow. The method may further include replacing the spaces between ceramic fibers included in the ceramic fiber tows with a ceramic matrix.

Abstract: An electrophoretic deposition method of forming a boron nitride (BN) nanotube interface coating on ceramic fibers has been developed. The method comprises immersing first and second electrodes in a suspension including surface-modified BN nanotubes, where the first electrode includes ceramic fibers positioned on a surface thereof. The surface-modified BN nanotubes comprise BN nanotubes with an electrically charged polymer adsorbed on surfaces thereof. A voltage is applied to the first and second electrodes, and the surface-modified BN nanotubes move toward the first electrode and deposit on the ceramic fibers. After the deposition of the surface-modified BN nanotubes, the ceramic fibers are removed from the suspension and heat treated. Accordingly, a BN nanotube interface coating is formed on the ceramic fibers.

Abstract: A bladed disk preform system is provided. Multiple sheets are formed or provided. Each of the sheets may include multiple ceramic fibers. Slots may be cut in each of the sheets before or after forming. The slots extend from an outer edge of the sheets inward toward a center of the sheets. The sheets are stacked on top of each other to form a bladed disk preform. The bladed disk preform is porous. The bladed disk preform may include a plurality of blade portions extending outward from a root portion. Each of the slots is positioned between adjacent blade portions.

Abstract: A fluid conduit may be provided comprising a ceramic matrix composite (CMC) cross-over tube and a flange. The CMC cross-over tube may comprise a first end configured to extend into a first combustor liner of a gas turbine engine, and a second end configured to extend into a second combustor liner of a gas turbine engine. The interior of the CMC cross-over tube may define a passageway. The flange may extend outwardly from an outer surface of the CMC cross-over tube. The flange may be configured to engage at least one of the first combustor liner and the second combustor liner.

Abstract: 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.

Abstract: A turbine shroud segment of a gas turbine engine includes a carrier segment, a blade track segment, and a plurality of seals arranged between the carrier segment and the blade track segment. The plurality of seals are arranged between the carrier segment and the blade track segment to block gases from passing between the carrier segment and the blade track segment.

Abstract: A method of making a ceramic matrix composite that exhibits chemical resistance has been developed. The method comprises depositing a compliant layer comprising boron nitride, silicon-doped boron nitride, and/or pyrolytic carbon on silicon carbide fibers, depositing a barrier layer having a high contact angle with molten silicon on the compliant layer, and depositing a wetting layer comprising silicon carbide, boron carbide, and/or pyrolytic carbon on the barrier layer. After depositing the wetting layer, a fiber preform comprising the silicon carbide fibers is infiltrated with a slurry. After slurry infiltration, the fiber preform is infiltrated with a melt comprising silicon, and then the melt is cooled, thereby forming a ceramic matrix composite.

Abstract: A method of treating a component adapted for use in a gas turbine engine is described herein. The component may comprise ceramic matrix composite materials. The treatment to the ceramic matrix composite component may reduce or eliminate the wear or damage of crack propagation in the ceramic matrix composite component.

Abstract: An assembly adapted for use in a gas turbine engine includes a carrier and a blade track segment that is supported by the carrier relative to a high temperature zone. The blade track segment provides a heat shield for use in high temperature applications protecting the carrier and other components.

Abstract: The disclosure describes a method for forming a surface layer of a ceramic matrix composite (CMC) article. The technique includes depositing a slurry on a surface of an infiltrated CMC. The slurry includes a carrier material, a binder, a plasticizer, and solid particles. The solid particles include a plurality of fine ceramic particles defining a fine particle average size less than about 5 micrometers. The method further includes drying the slurry to form an article having an outer surface layer that includes the solid particles on the infiltrated CMC. The method further includes machining at least a portion of the outer surface layer of the article. The method further includes infiltrating the article with a molten infiltrant to form a composite article.

Abstract: A method of forming a ceramic matrix composite (CMC) component having an engineered surface includes applying a surface slurry comprising first particulate solids in a liquid carrier to an outer surface of a ceramic fiber preform. The surface slurry is dried to remove the liquid carrier, and thus a surface slurry layer comprising the first particulate solids is formed on the outer surface. The surface slurry layer is polished to a predetermined thickness and/or surface finish. After polishing, a ceramic tape comprising second particulate solids is applied to the surface slurry layer, and pressure is applied to attach the ceramic tape to the surface slurry layer and to induce consolidation of the ceramic tape and the surface slurry layer. Thus, a multilayer surface region comprising the surface slurry layer and a ceramic tape layer is formed on the ceramic fiber preform.

Abstract: The disclosure describes techniques for forming a surface layer of an article including a CMC using a cast. In some examples, the surface layer includes three-dimensional surface features, which may increase adhesion between the CMC and a coating on the CMC. In some examples, the surface layer may include excess material, with or without three-dimensional surface features, which is on the CMC. The excess material may be machined to remove some of the excess material and facilitate conforming the article to dimensional tolerances, e.g., for fitting the article to another component. The excess material may reduce a likelihood that the CMC (e.g., reinforcement material in the CMC) is damaged by the machining.

Abstract: An assembly adapted for use in a gas turbine engine or other engine has a carrier component and a supported component, illustratively used as a heat shield. The assembly includes a mounting system for coupling the supported component to the carrier component. In an illustrative embodiment, the assembly is a turbine shroud segment for blocking gasses from passing over turbine blades included in the gas turbine engine.

Abstract: A method to produce a protective surface layer having a predetermined topography on a ceramic matrix composite is described. The method includes applying a slurry layer to a surface of a fiber preform, and drying the slurry layer to form a particulate layer. A surface of the particulate layer is machined to improve surface smoothness and to form a machined surface. A ceramic tape is attached to the machined surface, and a tool comprising one or more features to be imprinted is placed on the ceramic tape, thereby forming a compression assembly. Heat and pressure are applied to the compression assembly to consolidate and bond the ceramic tape to the machined surface, while the one or more features of the tool are imprinted. Thus, a protective surface layer having a predetermined topography is formed.

Abstract: A method for infiltrating a porous preform for a gas turbine engine is provided, which comprises providing a chamber for infiltrating a porous preform. The porous preform is positioned within a slurry confinement fixture within the chamber. A vacuum is created in the chamber. A solvent is added to the slurry confinement fixture until a pressure in the chamber is substantially equal to an equilibrium partial pressure of the solvent. A slurry is added to the slurry confinement fixture. The slurry includes the solvent and a particulate. The pressure in the chamber is increased, and the slurry is urged into the porous preform.

Abstract: A turbine vane comprising ceramic matrix composite materials. The turbine vane includes an vane support core, an airfoil, and a pair of end walls that are spaced apart from one another to define a gas path. The turbine vane is formed from a plurality of ceramic plies or preforms that are infiltrated with ceramic matrix material to form a one-piece ceramic matrix composite turbine vane.