An example article may include a component, a substrate including a first ceramic, a joining layer between the component and the substrate, and a joint surface coating between the substrate and the joining layer. The joint surface coating may include a diffusion barrier layer including a second ceramic material, and a compliance layer including at least one of a metal or a metalloid. An example technique may include holding a first joining surface of a coated component adjacent a second joining surface of a second component. The example technique may further include heating at least one of the coated component, the second component, and a braze material, and brazing the coated component by allowing the braze material to flow in a region between the first joining surface and the second joining surface.

A method for forming a hole within a ceramic matrix composite component includes forming a first core portion for a ceramic matrix composite component; embedding a hollow member into the first core portion at a desired location; wrapping the first core portion with a first ceramic matrix composite material; inserting a rod through the hollow member and into the first core portion; removing the hollow member; assembling a second core portion to the first core portion such that the rod extends into the second core portion; and wrapping the first core portion and the second core portion with a second ceramic matrix composite material.

A turbine blade having an airfoil portion includes a first ceramic matrix composite (CMC) component having a first outer surface and a second ceramic matrix composite (CMC) component having a second outer surface. The second CMC component is positioned adjacent the first CMC component such that the first outer surface and the second outer surface align with one another and at least partially define the airfoil portion. A ceramic bead is at least partially formed at an interface between the first CMC component and the second CMC component. The formation of the bead melts a portion of the first CMC component and the second CMC component, such that the ceramic bead, the first CMC component, and the second CMC component become a single contiguous component and the bead fixedly attaches the first CMC component and the second CMC component. The bead includes a bead outer surface that extends outward beyond the first outer surface and the second outer surface and an overlayer is deposited onto the airfoil portion, the overlayer bonded to the first outer surface, the second outer surface, and the bead outer surface.

A lattice structure includes multiple identical unit cells formed from joined plates. In the lattice structure, some of the plates are rectangular plates, some of the plates are triangular plates, and some of the plates are trapezoidal plates. Further, any two of the joined rectangular plates have corresponding surface normals perpendicular to each other and at least two edges of each one of the triangular plates are joined to one of a surface or an edge of one of the plurality of joined plates. Further, at least three edges of each one of the trapezoidal plates are joined to one of a surface or an edge of one of the plurality of joined plates, and any one of a plurality of surface normals for the triangular plates and the trapezoidal plates are nonparallel to any one of a plurality of surface normals of rectangular plates.

Methods of forming ceramic matrix composite structures include joining at least two lamina together to form a flexible ceramic matrix composite structure. Ceramic matrix composite structures include at least one region of reduced inter-laminar bonding at a selected location between lamina thereof. Thermal protection systems include at least one seal comprising a ceramic matrix composite material and have at least one region of reduced inter-laminar bonding at a selected location between lamina used to form the seal. Methods of forming thermal protection systems include providing one or more such seals between adjacent panels of a thermal protection system.

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.

Disclosed herein are prepregs for ceramic matrix composites, processes for the preparation of a green bodies using the prepregs disclosed herein, and processes for the preparation of the ceramic matrix composites from the green bodies prepared according processes provided herein.

A method of producing a ceramic matrix composite including a protective ceramic coating thereon comprises applying a surface slurry onto an outer surface of an impregnated fiber preform. The surface slurry includes particulate ceramic solids dispersed in a flowable preceramic polymer comprising silicon, and the impregnated fiber preform comprises a framework of ceramic fibers loaded with particulate matter. The flowable preceramic polymer is cured, thereby forming on the outer surface a composite layer comprising a cured preceramic polymer with the particulate ceramic solids dispersed therein. The cured preceramic polymer is then pyrolyzed to form a porous ceramic layer comprising silicon carbide, and the impregnated fiber preform and the porous ceramic layer are infiltrated with a molten material comprising silicon. After infiltration, the molten material is cooled to form a ceramic matrix composite body with a protective ceramic coating thereon.

A method for producing a three-dimensional object, the method including: disposing powder; disposing fibers; and applying liquid for binding the powder and the fibers to at least one selected from the group consisting of the powder and the fibers.

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.