Abstract: An article includes a ceramic-based substrate and a barrier layer on the ceramic-based substrate. The barrier layer includes a matrix of barium-magnesium alumino-silicate or SiO2, a dispersion of silicon oxycarbide particles in the matrix, and a dispersion of particles, of the other of barium-magnesium alumino-silicate or SiO2, in the matrix.

Abstract: A turbine airfoil for a gas turbine engine according to an exemplary embodiment of this disclosure includes among other possible things, a tip portion including a pocket portion that transitions into a shelf portion and a plurality of cooling holes for communicating cooling airflow to at least one of the pocket portion and the shelf portion.

Abstract: A method of fabricating a ceramic matrix composite includes infiltrating pores of a porous structure with a preceramic matrix polymer using a composite molding technique. The porous structure includes fibers and an exposed carbon coating on the fibers. The preceramic matrix polymer wets the exposed carbon coating. The preceramic matrix polymer is then pyrolyzed to convert the preceramic matrix polymer to a ceramic matrix.

Abstract: A turbine vane includes an inner platform and an outer platform joined together by an airfoil. The airfoil has a leading edge and a trailing edge joined together by a pressure side and a suction side disposed opposite the pressure side. The inner platform defines a plurality of first inner cooling holes and a plurality of second inner cooling holes that are fluidly connected to an inner cooling passage. The plurality of first inner cooling holes are disposed proximate the leading edge and extend towards the suction side and the plurality of second inner cooling holes are disposed proximate the trailing edge and the suction side and extend towards the leading edge.

Abstract: An article includes a ceramic-based substrate and a barrier layer on the ceramic-based substrate. The barrier layer includes a matrix of barium-magnesium alumino-silicate or SiO2, a dispersion of silicon oxycarbide particles in the matrix, and a dispersion of particles, of the other of barium-magnesium alumino-silicate or SiO2, in the matrix.

Abstract: A turbine engine includes a first compressor and a second compressor fluidly parallel to the first compressor. A reverse flow combustor is fluidly connected to the first compressor and the second compressor. A first turbine and a second turbine are fluidly connected in series, and fluidly connected to an output of the reverse flow combustor.

Abstract: An auxiliary power unit may comprise a twin centrifugal compressor including a first blade. A turbine may be disposed aft of the twin centrifugal compressor. The turbine may include a second blade. The first blade comprises a first material and the second blade comprises a second material. The first material may the same as the second material. The twin centrifugal compressor may include forward centrifugal compressor and an aft centrifugal compressor disposed aft of the forward centrifugal compressor.

Abstract: A method for fabricating a ceramic material includes impregnating a porous structure with a mixture that includes a preceramic polymer and a filler. The filler includes at least one free metal. The preceramic polymer material is then rigidized to form a green body. The green body is then thermally treated to convert the rigidized preceramic polymer material into a ceramic matrix located within pores of the porous structure. The same thermal treatment or a second, further thermal treatment is used to cause the at least one free metal to move to internal porosity defined by the ceramic matrix or pores of the porous structure.

Abstract: Aspects are directed to removing a portion of a component that includes wear to generate a void in the component, where a material of the component has a first microstructure, depositing a filler material in the void, subjecting the filler material to a cold working technique to compress the filler material, and applying a heat treatment to cause the filler material to have a second microstructure that is matched to the first microstructure. Aspects are directed to a case of an engine, including: a first portion with a first material that has a first microstructure, and a second portion with a second material that has a second microstructure, where the second microstructure is matched to the first microstructure, where the second material includes a plurality of layers, and where at least one layer of the plurality of layers includes a compressive residual stress.

Abstract: A method of fabricating a ceramic article includes providing a porous body that includes a plurality of fiber bundles that has an intra-bundle porosity and an inter-bundle porosity, infiltrating the intra-bundle porosity and the inter-bundle porosity with a mixture of particles in a liquid carrier, the particles having an average size selected with respect to at least the intra-bundle porosity, removing the liquid carrier from the porous body to deposit the particles in the intra-bundle porosity and in the inter-bundle porosity, infiltrating a preceramic polymer into a remaining intra-bundle porosity and a remaining inter-bundle porosity, and thermally converting the preceramic polymer to a ceramic material.

Abstract: A turbine vane includes an inner platform and an outer platform joined together by an airfoil. The airfoil has a leading edge and a trailing edge joined together by a pressure side and a suction side disposed opposite the pressure side. The inner platform defines a plurality of first inner cooling holes and a plurality of second inner cooling holes that are fluidly connected to an inner cooling passage. The plurality of first inner cooling holes are disposed proximate the leading edge and extend towards the suction side and the plurality of second inner cooling holes are disposed proximate the trailing edge and the suction side and extend towards the leading edge.

Abstract: A method of fabricating a ceramic article includes providing a porous body that includes a plurality of fiber bundles that has an intra-bundle porosity and an inter-bundle porosity, infiltrating the intra-bundle porosity and the inter-bundle porosity with a mixture of particles in a liquid carrier, the particles having an average size selected with respect to at least the intra-bundle porosity, removing the liquid carrier from the porous body to deposit the particles in the intra-bundle porosity and in the inter-bundle porosity, infiltrating a preceramic polymer into a remaining intra-bundle porosity and a remaining inter-bundle porosity, and thermally converting the preceramic polymer to a ceramic material.

Abstract: A turbine engine includes a first compressor and a second compressor fluidly parallel to the first compressor. A reverse flow combustor is fluidly connected to the first compressor and the second compressor. A first turbine and a second turbine are fluidly connected in series, and fluidly connected to an output of the reverse flow combustor.

Abstract: Disclosed is a method for providing a crystalline ceramic material. In an example, the method includes providing a silicon-containing preceramic polymer material that can be thermally converted to one or more crystalline polymorphs. The silicon-containing preceramic polymer material includes dispersed therein an effective amount of dopant particles. The silicon-containing preceramic polymer material is then thermally converted to the silicon-containing ceramic material. The effective amount of dopant particles enhance the formation of at least one of the one or more crystalline polymorphs, relative to the silicon-containing preceramic polymer without the dopant particles, with respect to at least one of formation of a selected polymorph of the one or more crystalline polymorphs formed, an amount formed of a selected polymorph of the one or more crystalline polymorphs formed, and a temperature of formation of the one or more crystalline polymorphs.

Abstract: An auxiliary power unit may comprise a twin centrifugal compressor including a first blade. A turbine may be disposed aft of the twin centrifugal compressor. The turbine may include a second blade. The first blade comprises a first material and the second blade comprises a second material. The first material may the same as the second material. The twin centrifugal compressor may include forward centrifugal compressor and an aft centrifugal compressor disposed aft of the forward centrifugal compressor.

Abstract: A method of fabricating a ceramic matrix composite includes infiltrating pores of a porous structure with a preceramic matrix polymer using a composite molding technique. The porous structure includes fibers and an exposed carbon coating on the fibers. The preceramic matrix polymer wets the exposed carbon coating. The preceramic matrix polymer is then pyrolyzed to convert the preceramic matrix polymer to a ceramic matrix.

Abstract: A ceramic shroud seal has a roughed inner surface for contacting a rotating turbomachine component.

Abstract: A ceramic article includes a ceramic matrix composite that has a porous reinforcement structure and a ceramic matrix within pores of the porous reinforcement structure. The ceramic matrix composite includes a surface zone and a glaze material within pores of the surface zone and on an exterior side of the surface zone as an exterior glaze layer.

Abstract: A method of preparing a fiber for use in forming a ceramic matrix composite material comprises the steps of removing a polymer coating from an outer surface of glass or ceramic fibers by providing heated and humidified gas across the glass or ceramic fibers for a period of time.

Abstract: A method for fabricating a ceramic material includes providing a mobilized filler material capable of infiltrating a porous ceramic matrix composite. The mobilized filler material includes at least one of a ceramic material and a free metal. The mobilized filler material is infiltrated into pores of the porous ceramic matrix composite. The mobilized filler material is then immobilized within the pores of the porous ceramic matrix composite.