Abstract: The present disclosure is directed to the use and manufacture of cooling features within a component used in a hot gas path, such as within a turbine. In one embodiment, channels are formed within an external surface of the component and filled with a removable material. The external surface and channels may then be coated with one or more layers, such as a structural layer and/or top coat. The removable material may then be removed to leave the channels free of the removable material.

Abstract: Methods of fabricating coated components using multiple types of fillers are provided. One method comprises forming one or more grooves in an outer surface of a substrate. Each groove has a base and extends at least partially along the outer surface of the substrate. The method further includes disposing a sacrificial filler within the groove(s), disposing a permanent filler over the sacrificial filler, disposing a coating over at least a portion of the substrate and over the permanent filler, and removing the first sacrificial filler from the groove(s), to define one or more channels for cooling the component. A component with a permanent filler is also provided.

Abstract: Methods of fabricating coated components using multiple types of fillers are provided. One method comprises forming one or more grooves in an outer surface of a substrate. Each groove has a base and extends at least partially along the outer surface. A sacrificial filler is deposited within the groove, a second filler is deposited over the sacrificial filler, and a coating is disposed over at least a portion of the outer surface and over the second filler. The method further includes removing the sacrificial filler and at least partially removing the second filler from the groove(s), to define one or more channels for cooling the component.

Abstract: Methods of fabricating coated components using multiple types of fillers are provided. One method comprises forming one or more grooves in an outer surface of a substrate. Each groove has a base and extends at least partially along the outer surface of the substrate. The method further includes disposing a sacrificial filler within the groove(s), disposing a permanent filler over the sacrificial filler, disposing a coating over at least a portion of the substrate and over the permanent filler, and removing the first sacrificial filler from the groove(s), to define one or more channels for cooling the component. A component with a permanent filler is also provided.

Abstract: Methods of fabricating coated components using multiple types of fillers are provided. One method comprises forming one or more grooves in an outer surface of a substrate. Each groove has a base and extends at least partially along the outer surface. A sacrificial filler is deposited within the groove, a second filler is deposited over the sacrificial filler, and a coating is disposed over at least a portion of the outer surface and over the second filler. The method further includes removing the sacrificial filler and at least partially removing the second filler from the groove(s), to define one or more channels for cooling the component.

Abstract: The present disclosure is directed to the use and manufacture of cooling features within a component used in a hot gas path, such as within a turbine. In one embodiment, channels are formed within an external surface of the component and filled with a removable material. The external surface and channels may then be coated with one or more layers, such as a structural layer and/or top coat. The removable material may then be removed to leave the channels free of the removable material.

Abstract: The present invention provides a method for forming a refractory metal-intermetallic composite. The method includes providing a first powder comprising a refractory metal suitable for forming a metal phase; providing a second powder comprising a silicide precursor suitable for forming an intermetallic phase; blending the first powder and the second powder to form a powder blend; consolidating and mechanically deforming the powder blend at a first temperature; and reacting the powder blend at a second temperature to form the metal phase and the intermetallic phase of the refractory metal-intermetallic composite, wherein the second temperature is higher than the first temperature.

Abstract: A method for evaluating the thermal exposure of a selected metal component which has been exposed to changing temperature conditions is described. The voltage distribution on a surface of the metal component, or on a metallic layer which lies over the component, is first obtained. The voltage distribution usually results from a compositional change in the metal component. The voltage distribution is then compared to a thermal exposure-voltage model which expresses voltage distribution as a function of exposure time and exposure temperature for a reference standard corresponding to the metal component. In this manner, the thermal exposure of the selected component can be obtained. A related device for evaluating the thermal exposure of a selected metal component is also described.

Abstract: A turbine component formed from a niobium silicide-based composition is described. The component can be compositionally-graded through at least a portion of its structure. A turbine blade formed from a composition which includes a niobium silicide alloy is also described. The blade includes an airfoil; an airfoil tip region; a platform on which the airfoil is mounted; and a dovetail root attached to an underside of the platform. The niobium silicide alloy in at least one portion of the turbine blade is compositionally different from the niobium silicide alloy in another portion of the blade. Processes for fabricating a niobium silicide-based turbine article are also described, using laser cladding techniques. Repair methods are also set forth in the application.

Abstract: Various braze alloy compositions are described, along with methods for using them. In one instance, a boron-free, high-temperature braze alloy includes selected amounts of chromium, hafnium, and nickel. The braze alloy can be used, for example, as a component in a wide gap braze mixture where a higher or lower melting point superalloy and/or brazing powder is used. The braze alloys may permit joining or repairing of superalloy articles with complex shapes, and may be used in high temperature applications. In some other braze alloy embodiments, a nickel- or cobalt-based braze composition can contain selected amounts of boron, but includes restricted amounts of chromium.

Abstract: Braze compositions containing flux compositions and processes for using such braze compositions, such as for use in the manufacturing, coating, repair, and build-up of superalloy components. The braze composition contains an aqueous binder system, multiple inorganic compounds, titanium hydride, and a metallic braze alloy. The braze composition is useful when brazing superalloys that are prone to oxidation at elevated brazing temperatures.

Abstract: A shell mold for casting molten material to form an article is described. The mold includes a shell for containing the molten material, formed from at least one of yttrium silicates, zirconium silicates, hafnium silicates, and rare earth silicates. The mold also includes a facecoat disposed on an inner surface of the shell that contacts the molten material. The facecoat can be made from the materials described above. A method of casting a niobium-silicide article is also described, using the shell mold described herein. A method of making the ceramic shell mold is described as well, along with a slurry composition used in the manufacture of the shell mold.

Abstract: A turbine component formed from a niobium silicide-based composition is described. The component can be compositionally-graded through at least a portion of its structure. A turbine blade formed from a composition which includes a niobium silicide alloy is also described. The blade includes an airfoil; an airfoil tip region; a platform on which the airfoil is mounted; and a dovetail root attached to an underside of the platform. The niobium silicide alloy in at least one portion of the turbine blade is compositionally different from the niobium silicide alloy in another portion of the blade. Processes for fabricating a niobium silicide-based turbine article are also described, using laser cladding techniques. Repair methods are also set forth in the application.

Abstract: A method for evaluating the thermal exposure of a selected metal component which has been exposed to changing temperature conditions is described. The voltage distribution on a surface of the metal component, or on a metallic layer which lies over the component, is first obtained. The voltage distribution usually results from a compositional change in the metal component. The voltage distribution is then compared to a thermal exposure-voltage model which expresses voltage distribution as a function of exposure time and exposure temperature for a reference standard corresponding to the metal component. In this manner, the thermal exposure of the selected component can be obtained. A related device for evaluating the thermal exposure of a selected metal component is also described.

Abstract: A method for removing an oxide material from a crack in a substrate, the method includes: applying a slurry paste comprising a fluoride salt to the crack; heating the slurry paste and the crack to at least a melting point of the fluoride salt to form a reaction product; and removing the reaction product.

Abstract: A on-line method is provided for detecting wear and/or damage to gas turbine parts. Preferred embodiments of the invention provide a gas turbine comprising parts with smart coatings and collection and detection means to measure wear and erosion of gas turbine parts. In other preferred embodiments, smart coatings are provided comprising chemical taggants that can be collected and detected downstream, thus providing an on-line or in situ evaluation technology for wear and damage to gas turbine parts.

Abstract: A on-line method is provided for detecting wear and/or damage to gas turbine parts. Preferred embodiments of the invention provide a gas turbine comprising parts with smart coatings and collection and detection means to measure wear and erosion of gas turbine parts. In other preferred embodiments, smart coatings are provided comprising chemical taggants that can be collected and detected downstream, thus providing an on-line or in situ evaluation technology for wear and damage to gas turbine parts.

Abstract: A method of repairing cracks, imperfections, and the like in a cast article of superalloy composition having a directionally oriented microstructure and growth axis. An aperture, usually frustois created in the article in the location of the crack or imperfection. A plug, having a second directionally oriented microstructure having a directional microstructure with a growth axis and a superalloy composition substantially identical to the article superalloy composition, is created. Such plug further possesses an inner end, an outer end, and a surface therebetween. The plug is inserted into the aperture whereby the plug growth axis is oriented in alignment with the article growth axis. Bonding material is applied between the surfaces of the plug and the aperture, before or after insertion of the plug into the aperture. The article is thereafter heated such that the bonding material joins the surface of the plug and the aperture.

Abstract: A roughened bond coat comprises a screen that includes interwoven wires defining openings and a metallic material disposed on the screen. The screen and metallic material form a roughened bond coat possessing an uneven, undulated, and irregular surface. The metallic material may be one of a slurry and a powder, and applied by coating and spraying, respectively. A thermal barrier coating system, which is formed with and incorporates the roughened bond coat, exhibits greater adhesion of a thermal barrier coating and bond coat due to an increased interfacial surface area provided by the uneven, undulated, and irregular surface.

Abstract: A composition comprises cobalt; chromium; carbon; boron; zirconium; aluminum; at least one refractory material; and nickel. The composition is used as a repair material for repairing superalloy articles in a repair process.