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 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 method of slurry infiltration and cleaning to fabricate a ceramic matrix composite (CMC) component with an internal cavity or bore comprises inserting a number of rods into a hollow portion of a porous fiber preform, thereby forming a rod arrangement substantially filling the hollow portion. Each of the rods has a low-friction surface comprising a coefficient of static friction of about 0.1 or less. The porous fiber preform is exposed to a slurry comprising particulate solids in a liquid carrier, and the slurry infiltrates the porous fiber preform. Some fraction of the particulate solids is deposited within interstices of the porous fiber preform to form an impregnated fiber preform, and another fraction of the particulate solids is deposited within the hollow portion as excess slurry. After slurry infiltration, the rods are withdrawn from the hollow portion, and at least some of the excess slurry is removed with the rods.

Abstract: A turbine shroud adapted for use in a gas turbine engine includes an attachment feature and a body. The attachment feature and the body are constructed of ceramic matrix composite materials. In an illustrative embodiment, the ceramic matrix composite materials form a blade track segment.

Abstract: A method of forming a composite article includes impregnating an inorganic fiber preform with a slurry composition. The slurry composition includes a particulate, a solvent, and a pre-gellant material. Gelling of the pre-gellant material in the slurry composition is initiated to immobilize the particulate and yield a gelled article, and substantially all solvent is removed from the gelled article to form a green composite article. The green composite article is then infiltrated with a molten infiltrant to form the composite article.

Abstract: A ceramic matrix composite component for use in a gas turbine engine and method for making the same are described herein. The component includes a body and an outer region. The body includes a silicon containing ceramic composite. The outer region is on an outer surface of the body.

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 method of fabricating cooling features on a CMC component may comprise compressing a fabric preform within tooling including holes and/or recesses facing the fabric preform. During the compression, portions of the fabric preform are pushed into the holes and/or recesses. Gases are delivered through the tooling to deposit a matrix material on exposed surfaces of the fabric preform while the fabric preform is being compressed. The matrix material builds up on the portions of the fabric preform pushed into the holes and/or recesses, and a rigidized preform with surface protrusions is formed. The tooling is removed, and the rigidized preform is densified, thereby forming a CMC component including raised surface features.

Abstract: A ceramic matrix composite (CMC) seal segment for use in a segmented turbine shroud for radially encasing a turbine in a gas turbine engine. The CMC seal segment comprises an arcuate flange having a surface facing the turbine and a portion defining a bore for receiving an elongated pin, with the bore having a length that is at least 70% of the length of the elongated pin received therein. The CMC seal segment is carried by the carrier by at least one of the elongated pins being received within the bore. The CMC seal segment portion defining a pin-receiving bore is radially spaced from the arcuate flange by a spacing flange extending radially outward from the arcuate flange.

Abstract: Example techniques may include depositing a slurry on at least a predetermined surface region of a ceramic matrix composite substrate. The slurry may include a solvent and particles comprising at least one of silicon metal or silicon carbide. The slurry may be dried to form a wicking layer on the predetermined surface region. The ceramic matrix composite substrate and the wicking layer may be heated to a temperature of at least 900° C. to wick at least one wickable species from the ceramic matrix composite substrate into the wicking layer. Substantially all of the wicking layer may be removed from the predetermined surface region. Example articles may include a ceramic matrix composite substrate. A wicking layer may be disposed on at least a predetermined surface region of the ceramic matrix composite substrate. The wicking layer may include at least one wicked species wicked from the ceramic matrix composite substrate.

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: An assembly for a gas turbine engine includes a carrier and a supported component comprising ceramic matrix composite materials. The assembly also includes a retention assembly for coupling the supported component to the carrier.

Abstract: A gas turbine engine assembly adapted to separate a high pressure zone from a low pressure zone includes a seal assembly configured to block gasses from passing through the interface of two adjacent components. The seal assembly includes a rod.

Abstract: An assembly adapted for use in a gas turbine engine has a carrier component and a supported component. The assembly including a mounting system for coupling the supported component to the carrier component and a seal adapted to resist the movement of gasses between 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 gas turbine engine includes a turbine having turbine blades and a shroud having a blade track for positioning radially outside of the blades. At least one of the blades and the blade track are secured in place using a dovetail connection between a dovetail receiver and a dovetail assembly formed to include a contoured root.

Abstract: A turbine wheel for use in a gas turbine engine having a plurality of blades attached to a rotor disk. The blades each fit within slots formed in the rotor disk to couple the blades to the rotor disk. Platform segments are arranged about each of the blades.

Abstract: A blade track assembly is disclosed. The blade track assembly comprises a plurality of ceramic matrix composite blade track segments arranged circumferentially adjacent to one another around a central axis. Each of the blade track segments includes an arcuate runner extending in a circumferential direction around a portion of the central axis and is coupled to circumferentially adjacent blade track segments.

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: 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.