Abstract:
Methods for preparing ceramic matrix composites using melt infiltration and chemical vapor infiltration are provided as well as the resulting ceramic matrix composites. The methods and products include the incorporation of sacrificial fibers to provide improved infiltration of the fluid infiltrant. The sacrificial fibers are removed, such as decomposed during pyrolysis, resulting in the formation of regular and elongate channels throughout the ceramic matrix composite. Infiltration of the fluid infiltrant can then take place using the elongate channels resulting in improved density and an improved ceramic matrix composite product.
Abstract:
A method of forming a pre-form ceramic matrix composite mold for a ceramic matrix composite (CMC) component including providing pieces of CMC remnant scrap material and randomly arranging the pieces of CMC remnant scrap material relative to one another. The method further includes debulking the pieces of CMC remnant scrap material into a rigidized shape, the rigidized shape having gaps between adjacent pieces of CMC remnant scrap material of about 10 microns and about 10 mm and a gap spacing between about 50 microns and about 50 mm, and forming the rigidized shape into a mold.
Abstract:
A process of producing a ceramic matrix composite gas turbine component and a ceramic matrix composite gas turbine component are provided. The process includes modifying a surface of the ceramic matrix composite gas turbine component to produce a modified surface with a surface roughness of less than 6 micrometers. The modifying is selected from the group of techniques consisting of applying unreinforced matrix plies to the surface, vapor depositing silicon on the surface, honing the surface, applying braze paste to the surface, and combinations thereof. The component includes a modified surface including a surface roughness of less than 6 micrometers. The modified surface being selected from the group consisting of unreinforced matrix plies applied to a surface of the ceramic matrix composite gas turbine component, silicon vapor deposited on the surface, a honed surface, a braze paste applied to the surface, and combinations thereof.
Abstract:
Methods of providing a fiber reinforced braze include providing a substrate, disposing at least a first fiber reinforcement layer on the substrate, wherein the at least first fiber reinforcement layer comprises a fiber material, disposing at least a first braze layer on the at least first fiber reinforcement layer, wherein a melt temperature of the braze layer is lower than a melt temperature of the fiber material, and heating the at least first fiber reinforcement layer and the at least first braze layer to bond the fiber reinforced braze to the substrate.
Abstract:
A ceramic matrix composite article and a process of fabricating a ceramic matrix composite are disclosed. The ceramic matrix composite article includes a matrix distribution pattern formed by a manifold and ceramic matrix composite plies laid up on the matrix distribution pattern, includes the manifold, or a combination thereof. The manifold includes one or more matrix distribution channels operably connected to a delivery interface, the delivery interface configured for providing matrix material to one or more of the ceramic matrix composite plies. The process includes providing the manifold, forming the matrix distribution pattern by transporting the matrix material through the manifold, and contacting the ceramic matrix composite plies with the matrix material.
Abstract:
A ceramic matrix composite (CMC) component includes at least one seal surface, the at least one seal surface disposed adjacent an interfacing surface for providing a seal therebetween; and a coating disposed on the seal surface. The coating includes an aluminum oxide and/or a silicon dioxide.
Abstract:
Various embodiments include methods for densifying a melt infiltrated ceramic matrix composite (CMC) article, and a densified melt infiltrated CMC article formed thereby. Particular embodiments include a method including: providing a porous CMC preform within a first region of a casting apparatus; providing a molten densifier within a pressure head area of a second region of the casting apparatus, the first and second regions being operably connected and the molten densifier including at least one source of silicon; and applying a first pressure to the molten densifier within the pressure head, thereby infiltrating voids within the porous CMC preform with the molten densifier and forming a densified melt infiltrated CMC article.
Abstract:
A method of making a preform and preform formed by the method. The method includes providing a first pre-preg ply including at least a first fiber and a first resin. The method also includes providing a second pre-preg ply including at least a second fiber and a second resin over at least a portion of the first pre-preg ply. Heat or electromagnetic radiation is used to at least partially cure the first and second resins to form a cured preform. Heat is applied to pyrolyze at least a portion of the resin of the cured preform to form a pyrolyzed preform. A mechanical stimulus including at least one of controlled drying, local explosions, or ultrasonic energy is applied to the pyrolyzed preform. The mechanically treated pyrolyzed preform is subsequently densified by melt infiltration to form a densified preform.
Abstract:
The present disclosure is directed to a method for forming a passage in a composite component. The method includes forming a cavity in a fiber preform. The cavity forms a portion of the passage. The method also includes inserting a core into the cavity and placing one or more fiber plies onto the fiber preform to form a fiber preform assembly. The method further includes thermally processing the fiber preform assembly and densifying the fiber preform assembly to form the composite component. The method also includes removing the core from the composite component.
Abstract:
An apparatus to reduce wear and friction between CMC-to-metal attachment and interface, including a metal layer configured for insertion between a surface interface between a CMC component and a metal component. The surface interface of the metal layer is compliant relative to asperities of the surface interface of the CMC component. A coefficient of friction between the surface interface of the CMC component and the metal component is about 1.0 or less at an operating temperature between about 300° C. to about 325° C. and a limiting temperature of the metal component.