A method for forming a ceramic matrix composite component includes forming a fibrous preform of the component with a plurality of fiber layers and a fill region disposed between one or more of the plurality of fiber layers. Ceramic particles are provided in the fill region, which is densified using chemical vapor infiltration.

A method of connecting two CMC substrates that includes providing two substrates; placing one substrate approximate to the other substrate, such that at least a portion of the two substrates overlap and define a brazing area; placing a brazing material approximate the brazing area; defining a primary raster pattern that encompasses the brazing area and a portion of the two substrates outside the brazing area; defining a secondary raster pattern that encompasses the brazing area; allowing a laser to scan the primary raster pattern to preheat the brazing area to a temperature below the brazing material's melting point; allowing the laser to scan the secondary raster pattern to heat the brazing area to a temperature that is above the brazing material's melting point; melting and allowing the brazing material to flow within the brazing area; and cooling the brazing area to form a brazed joint connecting the two substrates.

A fiber-reinforced component for use in a gas turbine engine includes a first braided fiber sleeve forming a cooling channel and a plurality of fiber plies enclosing the first braided fiber sleeve, with the plurality of fiber plies forming first and second walls separated by the first braided fiber sleeve. The fiber-reinforced component further includes a matrix material between fibers of the braided fiber sleeve and the plurality of fiber plies.

Ceramic matrix composite articles include, for example a first plurality of plies of ceramic fibers in a ceramic matrix defining a first extent, and a local at least one second ply in said ceramic matrix defining a second extent on and/or in said first plurality of plies with the second extent being less than said first extent. The first plurality of plies has a first property, the at least one second ply has at least one second property, and said first property being different from said at least one second property. The different properties may include one or more different mechanical (stress/strain) properties, one or more different thermal conductivity properties, one or more different electrical conductivity properties, one or more different other properties, and combinations thereof.

A seal system includes a ceramic component that has a non-core-gaspath surface region that defines a first surface roughness and a core gaspath surface region. A metallic component is situated adjacent the non-core-gaspath surface region. A coating system is disposed on the ceramic component. The coating system includes a silicon-containing layer on the non-core-gaspath surface region and a barrier layer that has a first section on the silicon-containing layer and a second section on the core-gaspath region and that is connected to the first section. The surface of the barrier layer has a second surface roughness that is less than the first surface roughness. The first section is in contact with the metallic component and the second section serves as an environmental barrier on the core-gaspath region.

An aerospace component may comprise a fiber reinforced composite material. The fiber reinforced composite material includes a plurality of fiber layers and a carbon matrix surrounding the plurality of fiber layers. A plurality of ceramic particles is dispersed in the carbon matrix. A first fiber layer of the plurality of fiber layers may include a carbon fiber, and a second fiber layer of the plurality of fiber layers may include a non-carbon fiber. A hardness of the non-carbon fiber is greater than a hardness of carbon fiber.

A seal system includes a ceramic component, a metallic component, a silicon-containing layer, and a barrier layer. The ceramic component has a first surface region that defines a first surface roughness. The metallic component is situated adjacent to the first surface region and has a second surface region facing the first surface region. The silicon-containing layer is on the first surface region of the ceramic component and has a contact surface that defines a second surface roughness which is less than the first surface roughness. The barrier layer is on the metallic component and in contact with the silicon-containing layer and serves to limit interaction between silicon of the silicon-containing layer and the metallic component. The barrier layer includes at least one of alumina or MCrAlY.

A seal system includes a ceramic component, a metallic component, a coating system. The ceramic component has a first surface region that defines a first surface roughness. The metallic component is situated adjacent to the first surface region and has a second surface region facing the first surface region. The coating system includes a silicon-containing layer on the surface region of the ceramic component and barrier layer on the silicon-containing layer. The silicon containing layer has a surface in contact with the barrier layer and the barrier layer has a surface in contact with the metallic component. The surface of the barrier layer has a second surface roughness that is less than the first surface roughness. The barrier layer serves to limit interaction between silicon of the silicon-containing layer and elements of the metallic component. The barrier layer includes at least one of mullite, zircon, or hafnon.

A method to produce a ceramic matrix composite with controlled surface characteristics includes: applying a scrim ply to a surface of a fiber preform, where the fiber preform includes silicon carbide fibers coated with boron nitride; infiltrating the fiber preform and the scrim ply with a slurry, thereby forming an impregnated ply on an impregnated fiber preform; infiltrating the impregnated fiber preform and the impregnated ply with a melt comprising silicon, and then cooling, thereby forming a ceramic matrix composite having a ceramic surface layer thereon, where the ceramic surface layer has a predetermined thickness and is devoid of boron; machining or grit blasting the ceramic surface layer to form an intermediate layer suitable for coating; and depositing an environmental barrier coating on the intermediate layer. Thus, a ceramic matrix composite coated with the environmental barrier coating is formed with the intermediate layer in between.

An airfoil including a plurality of composite plies extending from a leading edge to a trailing edge and between a tip and a root. The airfoil further includes a frangible airfoil portion at the tip extending between the leading edge and the trailing edge and extending between the tip and a frangible line along a span including a first plurality of composite plies. The frangible airfoil portion includes a first plurality of composite plies including fibers having a first fiber modulus. The airfoil further includes a residual airfoil portion extending from the frangible line to the root along the span including a second plurality of composite plies. The second plurality of composite plies including one or more plies having a second fiber modulus. The second fiber modulus is greater than the first fiber modulus. Further, the residual airfoil portion meets the frangible airfoil portion at the frangible line.