Abstract: Methods for forming a unitary ceramic component are provided. The method may include: positioning a braze reactant layer in a contact area between a first densified ceramic component and a second densified ceramic component; positioning a pack material around at least a portion of the first densified ceramic component or the second densified ceramic component; positioning at least one infiltrate source in fluid communication with the braze reactant layer; and thereafter, heating the at least one infiltrate source, the pack material, the first densified ceramic component, and the second densified ceramic component to a braze temperature that is at or above a melting point of at least one phase of the infiltrate composition such that at least one phase of infiltrate composition melts and flows into the braze reactant layer and reacts with a ceramic precursor compound therein to form a ceramic material.

Abstract: A method for modifying a composite component may include positioning a barrier segment between an infiltrated segment of the composite component and a green segment to form an assembly; and initiating an infiltration process. The barrier segment may have a barrier segment permeability that is lower than a permeability of the infiltrated segment, a permeability of the green segment, or both. A composite component may include an infiltrated segment infiltrated with a molten material during a prior infiltration process; a green segment that is uninfiltrated; and a barrier segment having a microstructure different from the infiltrated segment, the green segment, or both. The microstructure of the barrier segment may be configured to slow a flow of material between the infiltrated segment and the green segment during a subsequent infiltration process.

Abstract: Methods for forming a unitary ceramic component are provided. The method may include: positioning a braze reactant layer in a contact area between a first densified ceramic component and a second densified ceramic component; positioning a pack material around at least a portion of the first densified ceramic component or the second densified ceramic component; positioning at least one infiltrate source in fluid communication with the braze reactant layer; and thereafter, heating the at least one infiltrate source, the pack material, the first densified ceramic component, and the second densified ceramic component to a braze temperature that is at or above a melting point of at least one phase of the infiltrate composition such that at least one phase of infiltrate composition melts and flows into the braze reactant layer and reacts with a ceramic precursor compound therein to form a ceramic material.

Abstract: Composite components and methods of densifying composite components are provided. For example, a composite component includes a first ply having a first plurality of unidirectional arrays of fiber tows extending in a first direction and a second ply having a second plurality of unidirectional arrays of fiber tows extending in a second direction. A first fluid pathway is defined in the first ply that has a first length greater than a first width, and a second fluid pathway is defined in the second ply that has a second length greater than a second width. The first and second fluid pathways may improve densification of the composite component by improving penetration of a densification fluid in the composite component.

Abstract: A method of redefining an opening in a composite component comprises filling the opening with a filling material, where the opening is defined in a body of the composite component and opens onto a surface defined by the composite component, and redefining the opening such that the opening extends into the body. Some methods comprise removing an existing coating from the surface of the composite component prior to filling the opening with the filling material and applying a new coating to the surface prior to redefining the opening such that the opening extends through the new coating and into the body. An exemplary composite component comprises a body, a surface with a coating thereon, an original opening defined through the body and filled with a filling material, and a new opening defined through the coating into the body, which may be defined at a new location from the original opening.

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: 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: 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: Methods for preparing ceramic products using liquid infusion technology and products formed from the same are provided. The methods and products include the incorporation of a particulate material and binder between ceramic fibers such that the fibers may be properly spaced during formation of the ceramic product. Ceramic matrix composite products can thereby be provided using near net shaping methods.

Abstract: CMC articles and methods for forming CMC articles are provided. In one example aspect, a method for forming a CMC article includes forming a CMC preform defining a first section and a second section. The first section has one or more plies that include sacrificial fibers. The second section of the CMC preform does not include sacrificial fibers. The first and second sections can be laid up to form the CMC prior to thermally processing, e.g., consolidation, firing, and infiltration. When the CMC preform is fired or burned out, the sacrificial fibers are removed or decomposed resulting in formation of channels within the first section of the pyrolyzed CMC preform. The channels are used as gas transport paths during chemical vapor infiltration to facilitate infiltration of a gaseous infiltrant into the fired CMC preform. The channels are then backfilled with a liquid infiltrant during a melt infiltration process.

Abstract: A ceramic matrix composite article includes a chemical vapor infiltration ceramic matrix composite base portion including ceramic fiber reinforcement material in a ceramic matrix material having between 0% and 5% free silicon. The ceramic matrix composite article further includes a melt infiltration ceramic matrix composite covering portion including a ceramic fiber reinforcement material in a ceramic matrix material having a greater percentage of free silicon than the chemical vapor infiltration ceramic matrix composite base portion.

Abstract: Provided is a method including obtaining ceramic matrix composite (CMC) with a first matrix portion including a silicon carbide and silicon phase dispersed therewithin, disposing a coating thereupon to form a sealed part, and forming thereupon another segment comprising a CMC, which may be another matrix portion including a silicon carbide and a silicon phase dispersed within therewithin. Also provided is a gas turbine component with a CMC segment including a matrix portion including a silicon carbide and a silicon phase dispersed therewithin, a sealing layer including silicon carbide enclosing the first segment, and a second segment on the sealing layer, wherein the second segment includes a melt-infiltrated CMC having a matrix portion including a silicon carbide and a silicon phase dispersed therewithin.

Abstract: Provided is a method including obtaining ceramic matrix composite (CMC) with a first matrix portion including a silicon carbide and silicon phase dispersed therewithin, disposing a coating thereupon to form a sealed part, and forming thereupon another segment comprising a CMC, which may be another matrix portion including a silicon carbide and a silicon phase dispersed within therewithin. Also provided is a gas turbine component with a CMC segment including a matrix portion including a silicon carbide and a silicon phase dispersed therewithin, a sealing layer including silicon carbide enclosing the first segment, and a second segment on the sealing layer, wherein the second segment includes a melt-infiltrated CMC having a matrix portion including a silicon carbide and a silicon phase dispersed therewithin.

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: Composite components and methods for adding a composite material to a composite component are provided. For example, a method comprises positioning a composite material segment against the composite component to form a component layup; applying an insulating material around at least a portion of the component layup to form an insulated layup; and densifying the insulated layup, where the composite component was previously densified before positioning the composite material segment against the composite component. In some embodiments, the composite material is ceramic matrix composite (CMC) and the composite material segment is a plurality of CMC plies. The composite component may be a CMC gas turbine engine component that comprises an original CMC component and a new CMC material segment joined to the original CMC component through the transfer of silicon between the original CMC component and the new CMC material segment during melt infiltration.

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: 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 for forming a ceramic matrix composite article includes laying up a first group of plies; laying up a second group of plies, the first and second groups of plies being adjacent to each other; compacting the first group of plies and the second group of plies in the same processing step; and performing a first infiltration process on the first group of plies. The method also includes performing a second infiltration process on the second group of plies, the first infiltration process being one of a melt infiltration process or a chemical vapor infiltration process, and the second infiltration process being the other of the melt infiltration process or the chemical vapor infiltration process.

Abstract: A method for forming a ceramic matrix composite article includes laying up a first group of plies; laying up a second group of plies, the first and second groups of plies being adjacent to each other; compacting the first group of plies and the second group of plies in the same processing step; and performing a first infiltration process on the first group of plies. The method also includes performing a second infiltration process on the second group of plies, the first infiltration process being one of a melt infiltration process or a chemical vapor infiltration process, and the second infiltration process being the other of the melt infiltration process or the chemical vapor infiltration process.

Abstract: A ceramic matrix composite article includes a chemical vapor infiltration ceramic matrix composite base portion including ceramic fiber reinforcement material in a ceramic matrix material having between 0% and 5% free silicon. The ceramic matrix composite article further includes a melt infiltration ceramic matrix composite covering portion including a ceramic fiber reinforcement material in a ceramic matrix material having a greater percentage of free silicon than the chemical vapor infiltration ceramic matrix composite base portion.