Abstract: The present application provides methods and apparatus for processing ceramic fibers for the manufacture of ceramic matrix composites (CMCs). One method may include providing at least one frame including a planar array of unidirectional ceramic fibers extending across a void thereof. The method may further include depositing a coating on the ceramic fibers of the at least one frame via a chemical vapor deposition (CVD) process. The method may also include impregnating the coated ceramic fibers with a slurry including a ceramic matrix precursor composition to form at least one CMC prepreg, such as a prepreg tape. The ceramic fibers may be substantially SiC fibers, for example.

Abstract: Ceramic matrix composite articles include, for example, a plurality of unidirectional arrays of fiber tows in a matrix having a monomodal pore size distribution, and a fiber volume fraction between about 15 percent and about 35 percent. The articles may be formed by, for example, providing a shaped preform comprising a prepreg tape layup of unidirectional arrays of fiber tows, a matrix precursor, and a pore former, curing the shaped preform to pyrolyze the matrix precursor and burnout the pore former so that the shaped preform comprises the unidirectional arrays of fiber tows and a porous matrix having a monomodal pore size distribution, and subjecting the cured shaped preform to chemical vapor infiltration to densify the porous matrix so that the ceramic matrix composite article has a fiber volume fraction between about 15 percent and about 35 percent.

Abstract: A method of repairing matrix microcracks in MI-CMC components includes heating “free” silicon phase present within the cracked matrix portion of the component to a temperature above the melting point of the silicon phase. During heating of the component an additional source of silicon phase is supplied to the component. The atmosphere about the component is controlled during the heating of the component. The MI-CMC component is cooled below the melting point of the silicon phase to cool and solidify the silicon phase that has migrated into the microcracks to thereby bond the crack faces together.

Abstract: The present disclosure is directed to a composite component for a gas turbine engine. The composite component includes a composite wall having a flow side surface and non-flow side surface. The non-flow side surface includes at least one composite cooling projection positioned on and extending outwardly from the non-flow side surface.

Abstract: A method can include applying a mask to a CMC structure, and subjecting the structure having an applied mask to a process for repair. In one embodiment, the applying a mask to a CMC structure can include applying a mask to a feature of a CMC structure.

Abstract: The present application provides methods and apparatus for processing ceramic fibers for the manufacture of ceramic matrix composites (CMCs). One method may include providing at least one frame including a planar array of unidirectional ceramic fibers extending across a void thereof. The method may further include at least one of depositing a coating on the ceramic fibers of the at least one frame via a chemical vapor deposition (CVD) process and impregnating the ceramic fibers with a slurry including a ceramic matrix precursor composition to form at least one CMC prepreg. In some embodiments, the ceramic fibers of the planar array may include a coating, and the method may include impregnating the coated ceramic fibers with a slurry including a ceramic matrix precursor composition to form at least one CMC prepreg.

Abstract: The present application provides methods and apparatus for processing ceramic fibers for the manufacture of ceramic matrix composites (CMCs). One method may include providing at least one frame including a planar array of unidirectional ceramic fibers extending across a void thereof. The method may further include depositing a coating on the ceramic fibers of the at least one frame via a chemical vapor deposition (CVD) process. The method may also include impregnating the coated ceramic fibers with a slurry including a ceramic matrix precursor composition to form at least one CMC prepreg, such as a prepreg tape. The ceramic fibers may be substantially SiC fibers, for example.

Abstract: A pre-impregnated composite tape is provided that includes: a matrix material; a plurality of fibers forming unidirectional arrays of tows encased within the matrix material; and a plurality of filler particles dispersed between adjacent fibers in the tape. The fibers have a mean fiber diameter of about 5 microns and about 40 microns, and are included within the tape at a volume fraction of about 15% and about 40%. The plurality of filler particles have a log-normal volumetric median particle size, such that the tape has a ratio of the log-normal volumetric median particle size to the mean fiber diameter that is about 0.05:1 to about 1:1. A method is also provided for forming a ceramic matrix composite.

Abstract: A pliable tape is generally provided that includes: a plurality of fibers forming unidirectional arrays of tows encased within a matrix material, with four adjacent fibers in the tape define an interstitial spacing therebetween. The matrix material comprises filler particles dispersed between adjacent fibers in the tape. In one embodiment, the filler particles have a median particle size defining the interstitial spacing such that the interstitial spacing is about 0.75 to about 1.1 of the median particle size. In another embodiment, the filler particles have a median particle size that is related to the surface-to-surface spacing between adjacent fibers, with the ratio of the surface-to-surface spacing between adjacent fibers and the median particle size being about 0.3:1 to about 1:1. Methods are also provided for forming a ceramic matrix composite.

Abstract: According to a method set forth herein a plurality of preform plies having first and second preform plies can be associated together to define a preform. The preform can be subject to chemical vapor infiltration (CVI) processing to define a ceramic matrix composite (CMC) structure.

Abstract: A ceramic matrix composite article includes a melt infiltration ceramic matrix composite substrate comprising a ceramic fiber reinforcement material in a ceramic matrix material having a free silicon proportion, and a chemical vapor infiltration ceramic matrix composite outer layer comprising a ceramic fiber reinforcement material in a ceramic matrix material having essentially no free silicon proportion disposed on an outer surface of at least a portion of the substrate.

Abstract: The present disclosure relates to ceramic matrix composites made by chemical vapor infiltration, methods of making the ceramic matrix composites, and ceramic matrix composite turbine components for use in a hot gas pathway. A method of fabricating a ceramic matrix composite is provided that can include the steps of: (i) forming a plurality of holes in a ceramic matrix composite preform of desired shape; and (ii) densifying the preform by a chemical vapor infiltration process to form a part or most of the matrix. A ceramic matrix composite is also provided that can be used in hot combustion gases made according to the aforementioned ceramic matrix composite fabrication method described herein.

Abstract: The disclosure relates generally to recession resistant gas turbine engine articles that comprise a silicon containing substrate, and related coatings and methods. The present disclosure is directed, inter alia, to an engine article comprising a silicon substrate which is coated with a chemically stable porous oxide layer. The present disclosure also relates to articles comprising a substrate and a bond coat on top comprising a two phase layer of interconnected silicon and interconnected oxide, followed by a layer of silicon. The present disclosure further relates to a recession resistant article comprising an oxide in a silicon containing substrate, such that components of the silicon containing substrate is interconnected with oxides dispersed in the substrate and form the bulk of the recession resistant silicon containing article.

Abstract: The disclosure relates generally to a method for reducing the thermal expansion/shrinkage behavior between fiber reinforced plies and monolithic matrix plies, and reducing the macroscopic defects that occur during process of making a ceramic matrix composite article.

Abstract: A method of repairing matrix microcracks in MI-CMC components includes heating “free” silicon phase present within the cracked matrix portion of the component to a temperature above the melting point of the silicon phase. During heating of the component an additional source of silicon phase is supplied to the component. The atmosphere about the component is controlled during the heating of the component. The MI-CMC component is cooled below the melting point of the silicon phase to cool and solidify the silicon phase that has migrated into the microcracks to thereby bond the crack faces together.

Abstract: A method of forming a ceramic matrix composite (CMC) component, a CMC component and a tip member are provided. The method of form the CMC component includes providing a component preform having a first end, a second end, and a cavity, the cavity having a pre-determined shape and a first engagement surface. The method includes forming a tip member from a pre-consolidated composite material, the tip member having a second engagement surface generally conforming to the first engagement surface. The method includes directing the second engagement surface to the first engagement surface. The method includes consolidating the component preform and tip member. The ceramic matrix composite component is formed having a desired geometry and the tip member stays in place in the cavity during operation of the ceramic matrix composite component.

Abstract: Silicon carbide ceramic matrix composites, and hybrid ceramic materials are provided. In one embodiment, the silicon carbide composites comprise reinforcement material further comprising a simplified coating, and in others, the composites comprise uncoated reinforcement material. The hybrid ceramic materials comprise at least two of a conventional ceramic matrix composite, a monolithic ceramic, the composite comprising uncoated reinforcement material, and the composite comprising reinforcement material comprising a simplified coating. Methods of providing the composites are also provided.

Abstract: A process for joining silicon-containing ceramic articles, and particularly ceramic articles and CMC articles that contain both silicon carbide and free silicon. The process entails providing a reactive metal-containing braze material between the articles, and then heating the braze material and the articles to react the reactive metal with the silicon within the articles to form a brazement containing a silicide phase of the reactive metal. The brazement and articles are then cooled to produce a component comprising the two articles and the silicide phase-containing brazement. The process is preferably carried out at temperatures below that which would thermally degrade constituents of the articles, and more preferably below the melting point of silicon.

Abstract: A support apparatus for a gas turbine shroud is disclosed. The apparatus includes an outer shroud block having a coupling connectable to a casing of the gas turbine and a shroud component having a forward flange and an aft flange. The shroud component is attached to the outer shroud block via the forward flange and the aft flange. The apparatus further includes a damper disposed between the outer shroud block and the shroud component and a biasing element disposed within the outer shroud block. A translational degree of freedom between the damper and the outer shroud block defines a direction of motion of the damper. The biasing element is in operable connection between the outer shroud block and the shroud component via the damper, a bias force of the biasing element directed along the direction of motion of the damper.

Abstract: A CMC article and process for producing the article to have a layer on its surface that protects a reinforcement material within the article from damage. The method entails providing a body containing a ceramic reinforcement material in a matrix material that contains a precursor of a ceramic matrix material. A fraction of the reinforcement material is present and possibly exposed at a surface of the body. The body surface is then provided with a surface layer formed of a slurry containing a particulate material but lacking the reinforcement material of the body. The body and surface layer are heated to form the article by converting the precursor within the body to form the ceramic matrix material in which the reinforcement material is contained, and by converting the surface layer to form the protective layer that covers any fraction of the reinforcement material exposed at the body surface.