Abstract: A method of forming a vane preform includes braiding a sleeve from ceramic fibers, inserting a flared mandrel into the sleeve, the flared mandrel comprising a body region and at least one contoured region, manipulating the sleeve using the flared mandrel to form contours in the sleeve corresponding to the contoured region of the flared mandrel, and laying up at least one ceramic ply with the sleeve to form the vane preform.

Abstract: A tooling assembly suitable for use in infiltrating a fibrous preform comprises an outer tooling fixture with a plurality of outer sidewalls defining an inner volume, each of the plurality of outer sidewalls having an outer wall thickness, and a window extending through the outer wall thickness of at least one outer sidewall of the plurality of sidewalls. The tooling assembly further comprises an inner tooling fixture positioned within the inner volume of the outer tooling fixture, the inner tooling having a plurality of inner sidewalls, each of the plurality of inner sidewalls having an inner wall thickness, and a plurality of holes extending through the inner wall thickness of at least one inner sidewall of the plurality of inner sidewalls. The at least one outer sidewall is positioned adjacent the at least one inner sidewall such that the window overlaps with at least a subset of the plurality of holes in the at least one inner sidewall.

Abstract: A tooling assembly suitable for use in infiltrating a fibrous preform comprises a perforated fixture having a thickness. The fixture comprises a plurality of holes extending through the thickness, and a first counterbore aligned with at least one hole of the plurality of holes, the first counterbore having a first length extending partially through the thickness.

Abstract: A space filler for forming a fibrous preform may comprise an additively manufactured ceramic material. The additively manufactured ceramic material may define a plurality of pores. A shape of the additively manufactured ceramic material may complement a shape of a void formed by fibrous regions of the fibrous preform.

Abstract: A ceramic matrix composite includes a plurality of ceramic fibers and an interface coating disposed on the plurality of ceramic fibers. The interface coating includes a carbon-based layer disposed on each ceramic fiber of the plurality of ceramic fibers and a boron-nitride based layer disposed on the first carbon-based layer. The ceramic matrix composite also includes a ceramic matrix surrounding the plurality of ceramic fibers. A ceramic matrix composite and a method of forming a ceramic matrix composite component are also disclosed.

Abstract: Disclosed herein is a composite co-fiber comprising a plurality of ceramic tows; one or more sacrificial yarns; where the sacrificial yarns are operative to undergo dissolution, decomposition or melting upon being subjected to an elevated temperature; and wherein the sacrificial yarns leave open spaces in the co-fiber upon being subjected to decomposition, dissolution or melting.

Abstract: A tackified ceramic fabric sheet includes a pre-preg layer having a fabric of woven ceramic tows and a tackifier compound surrounding the tows and comprising 15% to 60% polyvinyl butyral with ethanol. The sheet further includes a removable first backing film layer on a first side of the pre-preg layer.

Abstract: A method of forming a ceramic matrix composite includes applying a tackifier of ethanol and 3% to 12% polyvinyl butyral to a ceramic material, removing the ethanol from the ceramic material, and removing the polyvinyl butyral. The step of applying the tackifier includes one of a spraying, pipetting, painting, and immersing technique.

Abstract: An airfoil includes an airfoil section that has an airfoil wall that circumscribes an internal airfoil cavity and defines leading and trailing ends and pressure and suction sides. The airfoil wall is formed of a ceramic matrix composite (CMC) laminate comprised of fiber plies disposed in a ceramic matrix. The fiber plies include a skin fiber ply that defines an exterior of the airfoil section and at least one inner fiber ply that lines the skin fiber ply. At least one inner fiber ply locally terminates at one of the leading end or the trailing end such that the airfoil wall has fewer of the fiber plies in the leading end or the trailing end than in each of the pressure side and the suction side.

Abstract: A method for forming ceramic matrix composite (CMC) component includes forming a fiber preform, positioning the fiber preform into a chemical vapor infiltration reactor chamber, and densifying the fiber preform. Densification includes infiltrating the fiber preform with a first gas comprising precursors of silicon carbide and infiltrating the fiber preform with a second gas comprising a first rare earth element, wherein the steps of infiltrating the fiber preform with the first gas and infiltrating the fiber preform with the second gas are conducted simultaneously to produce a first rare earth-doped silicon carbide matrix in a first region of the component.

Abstract: A tackified ceramic fabric sheet includes a pre-preg layer having a fabric of woven ceramic tows and a tackifier compound surrounding the tows and comprising 15% to 60% polyvinyl butyral with ethanol. The sheet further includes a removable first backing film layer on a first side of the pre-preg layer.

Abstract: A space filler for forming a fibrous preform may comprise an additively manufactured ceramic material. The additively manufactured ceramic material may define a plurality of pores. A shape of the additively manufactured ceramic material may complement a shape of a void formed by fibrous regions of the fibrous preform.

Abstract: An assembly for a gas turbine engine according to an example of the present disclosure includes at least one platform having a main body extending between a first mate face and a second mate face to establish a gas path surface. The main body has an internal passage extending circumferentially between a first opening along the first mate face and a second opening along the second mate face relative to an assembly axis. A perimeter of the first mate face establishes a first area, a perimeter of the second opening establishes a second area, and the second area is greater than the first area. An airfoil section extends radially from the at least one platform.

Abstract: An airfoil includes an airfoil wall that defines a leading end, a trailing end, and pressure and suction sides that join the leading end and the trailing end. The airfoil wall includes a wishbone-shaped fiber layer structure that has a pair of arms that merge into a single leg. The pair of arms are formed by first and second S-shaped fiber layers each of which is comprised of a network of fiber tows. The first and second S-shaped fiber layers merge to form the single leg. The single leg comprises fiber tows from each of the first and second S-shaped fiber layers that are interwoven, and the single leg forms at least a portion of the trailing end of the airfoil wall.

Abstract: A method for manufacturing ceramic matrix composites (CMC) and CMCs made by the method are disclosed. The method can be a manual process or an automated process, such as using a robotic system, that is used for controlled delivery of ceramic particles in a CMC fabric. The method includes identifying voids present between adjacent tows of the CMC fabric and dispensing ceramic particles into the voids. Applying the ceramic particles in the center of the voids reduces the size and volume fraction of the voids/defects, improving the homogeneity of surface texture of the preform, homogeneity of microstructure, and part model shape conformity. The method for manufacturing CMCs creates CMCs having a homogenous distribution of small pores after matrix formation that improves the interlaminar mechanical and thermal properties of the CMCs.

Abstract: A method of forming a ceramic matrix composite includes applying a binder comprising water and 5% to 15% polyvinyl alcohol to a ceramic material and decomposing the binder to leave behind a discontinuous carbon layer within the ceramic material. The step of applying the binder includes one of a spraying, pipetting, painting, immersing, and pre-pregging technique.

Abstract: A method of preparing a ceramic fabric for use in a ceramic matrix composite includes transforming a ceramic tow from a first tow geometry to a second tow geometry, thereby reducing a first dimension of the ceramic tow and increasing a second dimension of the ceramic tow orthogonal to the first dimension to produce a flattened tow. The method includes weaving or braiding the flattened ceramic tow to form a ceramic fabric.

Abstract: A method of spreading fiber tows includes assembling a fibrous composite from a plurality of tows, applying an aqueous solution to the fibrous composite, freezing the fibrous composite after applying the aqueous solution, freeze drying the fibrous composite to remove water from the fibrous composite, and heating the fibrous composite after freeze drying to remove a cryoprotectant from the fibrous composite. The aqueous solution comprises water and the cryoprotectant and freezing the fibrous composite spreads filaments within the plurality of fiber tows.

Abstract: A method of preparing a ceramic fabric and ceramic matrix composite components constructed from the ceramic fabric include transforming ceramic tows, or ceramic fabrics, to varying degrees from a first tow geometry to a second tow geometry, thereby reducing a first dimension of the ceramic tows and increasing a second dimension of the ceramic tows orthogonal to the first dimension. Plies constructed with flattened tows, or as-received tows, have various inter-tow pore sizes that are arranged with increasing inter-tow pore size towards exterior surfaces of the preform structure.

Abstract: Disclosed herein is a composite ply comprising fill and warp tows; or optional axial and bias tows; wherein one or more of the fill tows and/or the warp tows or wherein one or more of the optional axial and/or bias tows comprise a polymer yarn while the remaining portion of the fill tows and/or the warp tows or the remaining portion of the bias and/or optional axial tows comprise the polymer yarn; and wherein the polymer yarn is melted to bond to the fill or warp tows to prevent removal from the ply.