Abstract: Turbine assemblies for a turbine of a gas turbine engine are disclosed herein. The turbine assemblies include a carrier and a blade track. The blade track extends around blades of a turbine wheel assembly to block gasses passed along a gas path from moving over the blades without causing the blades to rotate during operation of the turbine assembly. The blade track includes a plurality of blade track segments arranged circumferentially adjacent to one another about a central axis to form a ring. A retention ring engages both the carrier and the blade track segments to facilitate coupling and sealing.

Abstract: A blade for a gas turbine engine, and methods of manufacture of such a blade having a continuous density gradient so that the portion of the blade nearest the rotator shaft is of a higher density than the portion of the blade furthest from the rotator shaft.

Abstract: A porous fiber preform enclosed within a mold may be melt infiltrated by pouring a molten material through an inlet of the mold, the porous fiber preform comprising ceramic fibers. A ceramic matrix composite component comprising the ceramic fibers may be formed by solidifying the molten material that is in the mold and in the porous fiber preform.

Abstract: A method for repairing a ceramic matrix composite (CMC) article including a ceramic material in a matrix including a metal alloy, wherein a localized region of the metal alloy has a defect. The method includes applying heat to the localized region for a time sufficient to increase the temperature of the metal alloy in the localized region above the melt temperature thereof and cause the metal alloy in the localized region to flow and seal the crack.

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: 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: A segmented turbine shroud for radially encasing a rotatable turbine in a gas turbine engine comprising a carrier, a ceramic matrix composite (CMC) seal segment, and an elongated pin. The carrier defines a pin-receiving carrier bore and the CMC seal segment defines a pin-receiving seal segment bore. The elongated pin extends through the carrier bore and the seal segment bore. The pin-receiving carrier bore includes a cantilevered member such that the carrier bore has a length sufficient to effect radial flexion between the carrier bore and the pin received within the carrier bore during operation of the turbine.

Abstract: A segmented turbine shroud for radially encasing a turbine in a gas turbine engine comprises a carrier comprising a flange; a ceramic matrix composite (CMC) seal segment comprising a portion defining a pin-receiving bore; an elongated pin extending through the pin-receiving bore; a bushing surrounding the elongated pin within the bore; and a flexible mounting member, the flexible mounting member being connected to the bushing and the carrier flange to thereby flexibly mount the CMC seal segment to the carrier.

Abstract: A method of making a fiber preform for ceramic matrix composite (CMC) fabrication comprises laminating an arrangement of fibers between polymer sheets comprising an organic polymer, which may function as a fugitive binder during fabrication, to form a flexible prepreg sheet. A plurality of the flexible prepreg sheets are laid up in a predetermined geometry to form a stack, and the stack is heated to soften the organic polymer and bond together the flexible prepreg sheets into a bonded prepreg structure. Upon cooling of the bonded prepreg structure, a rigid preform is formed. The rigid preform is heated at a sufficient temperature to pyrolyze the organic polymer. Thus, a porous preform that may undergo further processing into a CMC is formed.

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: In some embodiments, an apparatus includes a disk, a coupling member and a set of blades. The coupling member has a first surface and a second surface, and defines a set of openings between the first surface and the second surface. The first surface is configured to be coupled to the outer surface of the disk. A portion of each blade from the set of blades is disposed within an opening from the set of openings when the first surface of the coupling member is coupled to the outer surface of the disk such that the blade is coupled to the disk.

Abstract: A ceramic matrix composite component and methods of making are described herein. The ceramic matrix composite may include a silicon containing matrix and refractory fibers embedded within the silicon containing matrix. The ceramic matrix composite component may further include a silicide layer sandwiched between the silicon containing matrix and the refractory fibers. A method of forming a ceramic matrix composite may include infiltrating a fluid that includes a refractory metal element containing compound into a fiber preform that includes fibers. The method may further include depositing the refractory metal element from the refractory metal element containing compound onto the fibers and forming, from the refractory metal element deposited onto the fibers, a refractory metal silicide.

Abstract: A method includes heating, using a heat source, a reactor vessel including a substrate in a radially central core region of the reactor vessel and introducing, using at least one reactor inlet in an outer wall of the reactor vessel, a precursor gas to the reactor vessel. The at least one reactor inlet is configured to swirling flow of the precursor gas around the radially central core region of the reactor vessel. The material deposits on the substrate from the precursor gas. The method includes removing, using at least one reactor outlet, an exhaust gas from the reactor vessel.

Abstract: A method of forming a composite article may include impregnating an inorganic fiber porous preform with a first slurry composition. The slurry composition includes particles, a solvent, and a pre-gellant material. Gelling of the pre-gellant material in the slurry composition is initiated to substantially immobilize the particles and yield a gelled article. The method also includes impregnating the gelled article with a second solution that includes a high char-yielding component, and pyrolyzing the high char-yielding component to yield carbon and form a green composite article. The green composite article is then infiltrated with a molten metal or alloy infiltrant to form the composite article. The molten infiltrant reacts with carbon, and the final composite article may include less residual metal or alloy than a composite article formed without using the second solution.

Abstract: A cartridge for a ceramic matrix composite (CMC) seal segment of a segmented turbine shroud of a gas turbine engine is provided. The cartridge comprises a carrier segment and a CMC seal segment. A surface of the carrier segment and a surface of the CMC seal segment form a mating region proximate the entire perimeter of the CMC seal segment. The carrier segment surface may comprise a channel, and a compressible mating element may be disposed within the channel. Air may be supplied to a cavity, formed by the carrier and CMC seal segment, and the mating region.

Abstract: A turbine shroud for positioning radially outside of blades of a turbine rotor includes a carrier, a blade track, and a track attachment system. The blade track is moved radially outwardly into a cavity of the carrier, and the track attachment system is adjusted to block radially inward movement of the blade track out of the cavity.

Abstract: A method of forming a moisture-tolerant coating on a silicon carbide fiber includes exposing a silicon carbide fiber to a gaseous N precursor comprising nitrogen at an elevated temperature, thereby introducing nitrogen into a surface region of the silicon carbide fiber, and exposing the silicon carbide fiber to a gaseous B precursor comprising boron at an elevated temperature, thereby introducing boron into the surface region of the silicon carbide fiber. Silicon-doped boron nitride is formed at the surface region of the silicon carbide fiber without exposing the silicon carbide fiber to a gaseous Si precursor comprising Si. Thus, a moisture-tolerant coating comprising the silicon-doped boron nitride is grown in-situ on the silicon carbide fiber.

Abstract: A method of melt infiltration for producing a ceramic matrix composite comprises applying a surface slurry onto one or more outer surfaces of an impregnated porous preform. The surface slurry comprises a solvent and particulate solids, and the preform comprises a framework of ceramic fibers loaded with particulate matter. The surface slurry is dried to form a porous layer comprising the particulate solids on the one or more outer surfaces of the impregnated porous preform. After forming the porous layer, an end portion of the impregnated porous preform that includes at least part of the porous layer is immersed in a molten material, and the molten material is infiltrated into the impregnated porous preform from the end portion. The porous layer serves as a wick to transport the molten material over the one or more outer surfaces, thereby enabling melt infiltration of the impregnated porous preform from other portions thereof.

Abstract: A method of melt infiltration for producing a ceramic matrix composite comprises applying a non-wetting coating onto one or more outer surfaces of a porous fiber preform. The non-wetting coating comprises a non-wetting material with which molten silicon has a contact angle of at least about 45°. After applying the non-wetting coating, an uncoated portion of the porous fiber preform is immersed into a molten material comprising silicon, and the molten material is infiltrated into the porous fiber preform through the uncoated portion. The non-wetting coating serves as a barrier to inhibit or prevent the molten material from penetrating the one or more outer surfaces. After infiltration of the molten material into the porous fiber preform, the molten material is cooled to form a ceramic matrix composite, and the non-wetting coating is removed.

Abstract: A shroud for radially encasing a turbine in a gas turbine engine is provided. The shroud comprises a carrier which defines a pin-receiving carrier bore, and a ceramic matrix composite (CMC) seal segment comprising an arcuate flange with a surface facing the turbine and a part that defines a pin-receiving seal segment bore. The seal segment bore is radially spaced from the arcuate flange by a spacing flange which extends radially outward from the arcuate flange to effect receipt within the seal segment bore of an elongated pin. The elongated pin extends through the carrier bore and the seal segment bore, and the elongated pin has a lateral cross-sectional dimension of at least three-eighths of an inch.