A method for producing an acoustic attenuation panel from a composite material with a ceramic oxide matrix is provided that includes draping a plurality of plies having fibrous reinforcements including fibers of ceramic material in a mold to define a first skin, depositing blocks made of fugitive material on the first skin such that a space between two blocks is defined, and draping a second plurality of plies on a surface formed by the blocks such that a second skin is defined. Rounded corners of the blocks define radii for connecting the first and second skins with walls of a honeycomb core of the acoustic panel. The method further includes using a liquid medium to infiltrate the skins and spaces with a precursor of a ceramic phase, removing the liquid medium by evaporation or polymerization, and sintering to consolidate the ceramic oxide material and removal the fugitive material.

Methods and systems are described for fabricating a component using 3D printing. A 3D printed piece is created including a body of the component, a support structure, and a first sacrificial interface region coupling the body of the component to the support structure. The body of the component is formed of a first metal or ceramic material and the first sacrificial interface region is formed at least partially of a second metal or ceramic material. The body of the component is then separated from the support structure by applying a chemical or electrochemical dissolution process to the 3D printed piece. Because the second metal or ceramic material is less resistant to the dissolution process than the first metal or ceramic material, the first sacrificial interface region at least partially dissolves, thereby separating the body of the metal component from the support structure, without dissolving the body of the component.

A composition which comprises a soluble or partially soluble phosphate, a refractory material and less than 1% of an oxide or hydroxide of magnesium or calcium. The composition may be mixed with water to form an investment casting slurry into which a wax pattern may be dipped. Slurry coated onto the pattern may be set by applying a stucco composition which comprises an oxide or hydroxide of magnesium or calcium. Coats of set slurry may be built up on the pattern to form an investment casting shell.

A fiber preform defining an annulus extending along a central longitudinal axis. The fiber preform includes a plurality of layers extending in an axial direction and a circumferential direction relative to the longitudinal axis. Each layer of the plurality of layers includes a plurality of elongate fibers. The plurality of elongate fibers include a plurality of elongate axial fibers extending substantially in the axial direction and a plurality of elongate circumferential fibers extending substantially in the circumferential direction. The fiber preform also includes a plurality of radial fibers extending substantially in the radial direction. The plurality of radial fibers mechanically bind one or more adjacent layers of the plurality of layers. At least 40% of the plurality of elongate fibers extend substantially in the axial direction.

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.

A method that includes winding a composite fabric around a mandrel to form a plurality of layers defining an annulus extending along a central longitudinal axis, where the composite fabric includes a plurality of elongate axial fibers extending substantially in an axial direction relative to the longitudinal axis and a plurality of elongate circumferential fibers extending substantially in a circumferential direction relative to the longitudinal axis; and introducing, into at least a portion of the plurality of layers, a plurality of radial fibers extending substantially in the radial direction relative to the longitudinal axis, where the plurality of radial fibers mechanically bind one or more adjacent layers of the plurality of layers.

A seal assembly for a gas turbine engine according to an example of the present disclosure includes, among other things, a seal that has a main body extending circumferentially between opposed mate faces. The main body has a sealing portion and an engagement portion extending outwardly from sealing portion along at least one of the mate faces. The main body includes one or more braided core plies having a first fiber construction and arranged to establish an internal cavity. An overwrap having one or more braided overwrap plies follows a perimeter of the one or more braided core plies to establish the engagement portion and the sealing portion. The one or more braided overwrap plies have a second fiber construction differing from the first fiber construction. A method of fabricating a seal for a gas turbine engine is also disclosed.

A seal assembly for a gas turbine engine according to an example of the present disclosure includes a seal that has a main body extending circumferentially between opposed mate faces. The main body has a sealing portion and an engagement portion extending outwardly from sealing portion along at least one of the mate faces. The main body has a core that has one or more core plies having a first fiber construction and arranged to establish an internal cavity. An overwrap has one or more overwrap plies having a second fiber construction and arranged to follow a perimeter of the one or more core plies to establish the engagement portion and the sealing portion, and the second fiber construction differs from the first fiber construction. The first fiber construction establishes a first target fiber volume fraction, the second fiber construction establishes a second target fiber volume fraction. A method of fabricating a seal for a gas turbine engine is also disclosed.

A method of forming a cast component and a method of forming a casting mold is provided. The method is performed by connecting at least one wax gate component to a ceramic core-shell mold. The ceramic core-shell mold includes at least a filter, a first core portion, a first shell portion, and at least one first cavity between the core portion and the first shell portion. The ceramic core-shell mold may be manufactured using an additive manufacturing process and may include an integrated ceramic filter. At least a portion of the ceramic core-shell mold and the wax gate component is coated with a second ceramic material. The wax gate component is then removed to form a second cavity in fluid communication with the first cavity.

A seal includes a ceramic matrix composite ply having woven ceramic-based fibers in a ceramic-based matrix. The ceramic matrix composite ply has at least one bend formed about a bend axis and defines at least one rounded portion. A sealed assembly and a method of making a seal are also disclosed.