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 stationary CT system comprising at least one annular x ray source assembly comprising a plurality of respective x ray sources spaced along the annular x ray source assembly. Each of the x ray sources comprises a respective stationary x ray target, an electron beam focusing chamber; an x ray channel; an electron beam source disposed in a spaced apart relationship with respect to the respective stationary x ray target; a vacuum chamber disposed in between the electron beam focusing chamber and an insulating chamber where the insulating chamber houses the electron beam source; a radiation window at a pre-defined angular displacement from the respective stationary x ray target and the x ray channel; and a target substrate attached to the respective stationary x ray target.

Abstract: An apparatus for friction stir welding, a weld tool for friction stir welding, and a method for making a weld tool for friction stir welding are presented. The weld tool comprises a tungsten-based refractory material. A method for manufacturing an article, where the method comprises providing the apparatus for friction stir welding, and the article produced by this method are also presented.

Abstract: A niobium-silicide refractory metal intermetallic composite adapted for use in a turbine component. The niobium-silicide refractory metal intermetallic composite comprises: between about 19 atomic percent and about 24 atomic percent titanium; between about 1 atomic percent and about 5 atomic percent hafnium; between about 16 atomic percent and about 22 atomic percent silicon; between about 7 atomic percent and about 14 atomic percent chromium; from about 1.5 atomic percent to about 3 atomic percent tin; and a balance of niobium. The niobium silicide refractory intermetallic composite contains a tetragonal phase, which comprises a volume fraction from 0.35 to 0.5 of the niobium silicide refractory intermetallic composite, and a hexagonal M3Si5 silicide phase (wherein M is at least one of Nb and Hf) which comprises a volume fraction comprises less than 0.25 of the niobium silicide refractory intermetallic composite.

Abstract: A process for positioning at least one defect in a billet being forged into an article is described. The size and location of the billet is first determined, using a non-destructive test such as ultrasonic inspection. The movement of the defect under selected forging conditions is then predicted, using a finite element analysis model. The billet can then be positioned and forged under conditions which cause the defect to move to a non-critical area of the article. In this manner, a billet which might otherwise be discarded or set aside can often be retained for a useful purpose. Related articles are also described.

Abstract: An apparatus for friction stir welding, a weld tool for friction stir welding, and a method for making a weld tool for friction stir welding are presented. The weld tool comprises a tungsten-based refractory material. A method for manufacturing an article, where the method comprises providing the apparatus for friction stir welding, and the article produced by this method are also presented.

Abstract: A stationary CT system comprising at least one annular x ray source assembly comprising a plurality of respective x ray sources spaced along the annular x ray source assembly. Each of the x ray sources comprises a respective stationary x ray target, an electron beam focusing chamber; an x ray channel; an electron beam source disposed in a spaced apart relationship with respect to the respective stationary x ray target; a vacuum chamber disposed in between the electron beam focusing chamber and an insulating chamber where the insulating chamber houses the electron beam source; a radiation window at a pre-defined angular displacement from the respective stationary x ray target and the x ray channel; and a target substrate attached to the respective stationary x ray target.

Abstract: A process for positioning at least one defect in a billet being forged into an article is described. The size and location of the billet is first determined, using a non-destructive test such as ultrasonic inspection. The movement of the defect under selected forging conditions is then predicted, using a finite element analysis model. The billet can then be positioned and forged under conditions which cause the defect to move to a non-critical area of the article. In this manner, a billet which might otherwise be discarded or set aside can often be retained for a useful purpose. Related articles are also described.

Abstract: A method and apparatus for casting a near-net-shape article from a high temperature material, such as a refractory metal intermetallic composite material. The apparatus includes: a means for forming a molten material comprising at least one of a metal and an alloy; a means for pouring the molten material; a mold assembly comprising a solid shell having a face coat interposed between the solid shell and molten material; and a heater assembly for maintaining the solid shell at a temperature. The molten material solidifies within the solid shell to form a near-net shape of the article. The near-net shape article may be a turbine assembly component, such as, but not limited to, a vane or airfoil.

Abstract: An environmentally resistant coating (34) for improving the oxidation resistance of a niobium-based refractory metal intermetallic composite (Nb-based RMIC) at high temperatures, the environmentally resistant coating (34) comprising silicon, titanium, chromium, and niobium. The invention includes a turbine system (10) having turbine components (11) comprising at least one Nb-based RMIC, the environmentally resistant coating (34) disposed on a surface (33) of the Nb-based RMIC, and a thermal barrier coating (42) disposed on an outer surface (40) of the environmentally resistant coating (34). Methods of making a turbine component (11) having the environmentally resistant coating (34) and coating a Nb-based RMIC substrate (32) with the environmentally resistant coating (34) are also disclosed.

Abstract: A method and apparatus for casting a near-net-shape article from a high temperature material, such as a refractory metal intermetallic composite material. The apparatus includes: a means for forming a molten material comprising at least one of a metal and an alloy; a means for pouring the molten material; a mold assembly comprising a solid shell having a face coat interposed between the solid shell and molten material; and a heater assembly for maintaining the solid shell at a temperature. The molten material solidifies within the solid shell to form a near-net shape of the article. The near-net shape article may be a turbine assembly component, such as, but not limited to, a vane or airfoil.

Abstract: A system and method for repairing turbine components. The system includes means for obtaining a rapidly solidified material having a means of forming a rapidly solidified repair material and a means for melting the rapidly solidified repair material at a repair site located in a region of the turbine component. The means for obtaining the rapidly solidified material include melt spinning, planar flow, and melt extraction systems. Means for melting the rapidly solidified repair material include a welding torch, an electron beam, a laser beam, a welding torch, a TIG welder, and a plasma torch.

Abstract: An article, such as an airfoil having a melting temperature of at least about 1500° C. and comprising a first piece and a second piece joined by a braze to the first piece. The first piece comprises one of a first niobium-based refractory metal intermetallic composite and a first molybdenum-based refractory metal intermetallic composite, and the second piece comprises one of a second niobium-based refractory metal intermetallic composite and a second molybdenum-based refractory metal intermetallic composite. The braze joining the first piece to the second piece comprises a first metallic element and a second metallic element, wherein the first metallic element is one of titanium, palladium, zirconium, niobium, and hafnium, and wherein the second metallic element is one of titanium, palladium, zirconium, niobium, hafnium, aluminum, chromium, vanadium, platinum, gold, iron, nickel, and cobalt, the first metallic element being different from the second metallic element.

Abstract: A titanium article for an ultrasonic inspection is provided in which the titanium article can be ultrasonic inspected for determining its acceptability in for microstructurally sensitive applications. The ultrasonic inspection method comprises providing a titanium article, directing ultrasonic energy of ultrasonic inspection to the titanium article; scattering reflected energy in the titanium article; determining an amount of noise generated by the ultrasonic inspection of the titanium article; and characterizing the titanium article as acceptable if the amount of noise as a function of ultrasonic frequency or wavelength is characteristic of predominantly Rayleigh scattering and the magnitude of the noise is less than a pre-determined noise level. The titanium article comprises an uniform-fine grain microstructure. The uniform-fine grain microstructure generates predominantly Rayleigh scattering when undergoing ultrasonic inspection. The invention also sets forth a method of forming a titanium article.

Abstract: An environmentally resistant coating (34) for improving the oxidation resistance of a niobium-based refractory metal intermetallic composite (Nb-based RMIC) at high temperatures, the environmentally resistant coating (34) comprising silicon, titanium, chromium, and niobium. The invention includes a turbine system (10) having turbine components (11) comprising at least one Nb-based RMIC, the environmentally resistant coating (34) disposed on a surface (33) of the Nb-based RMIC, and a thermal barrier coating (42) disposed on an outer surface (40) of the environmentally resistant coating (34). Methods of making a turbine component (11) having the environmentally resistant coating (34) and coating a Nb-based RMIC substrate (32) with the environmentally resistant coating (34) are also disclosed.

Abstract: An airfoil having a melting temperature of at least about 1500° C. and comprising a first piece and a second piece joined by a braze to the first piece. The first piece comprises one of a first niobium-based refractory metal intermetallic composite and a first-based refractory metal intermetallic composite, and the second piece comprises one of a second niobium-based refractory metal intermetallic composite and a second molybdenum-based refractory metal intermetallic composite. The braze joining the first piece to the second piece is a semi-solid braze that comprises a first component and a second component.

Abstract: An airfoil having a melting temperature of at least about 1500° C. and comprising a first piece and a second piece joined by a braze to the first piece. The first piece comprises one of a first niobium-based refractory metal intermetallic composite and a first molybdenum-based refractory metal intermetallic composite, and the second piece comprises one of a second niobium-based refractory metal intermetallic composite and a second molybdenum-based refractory metal intermetallic composite. The braze joining the first piece to the second piece comprises one of germanium and silicon, and one of chromium, titanium, gold, aluminum, palladium, platinum, and nickel. This abstract is submitted in compliance with 37 C.F.R. 1.72(b) with the understanding that it will not be used to interpret or limit the scope of or meaning of the claims.

Abstract: An airfoil having a melting temperature of at least about 1500° C. and comprising a first piece and a second piece joined at a bonded region to the first piece by a diffusion bond. The first piece comprises one of a first niobium-based refractory metal intermetallic composite and a first molybdenum-based refractory metal intermetallic composite. The second piece comprises one of a second niobium-based refractory metal intermetallic composite and a second molybdenum-based refractory metal intermetallic composite. The diffusion bond is formed from a first metallic element disposed on a first surface of the first piece and a second metallic element disposed on at least one of the first surface and a second surface of the second piece, the second surface contacting the first surface, wherein the first and second metal form a composition having a melting temperature less than about 1400° C. This abstract is submitted in compliance with 37 C.F.R. 1.

Abstract: A niobium-silicide refractory metal intermetallic composite adapted for use in a turbine component. The niobium-silicide refractory metal intermetallic composite comprises: between about 19 atomic percent and about 24 atomic percent titanium; between about 1 atomic percent and about 5 atomic percent hafnium; between about 16 atomic percent and about 22 atomic percent silicon; between about 7 atomic percent and about 14 atomic percent chromium; from about 1.5 atomic percent to about 3 atomic percent tin; and a balance of niobium. The niobium silicide refractory intermetallic composite contains a tetragonal phase, which comprises a volume fraction from 0.35 to 0.5 of the niobium silicide refractory intermetallic composite, and a hexagonal M3Si5 silicide phase (wherein M is at least one of Nb and Hf) which comprises a volume fraction comprises less than 0.25 of the niobium silicide refractory intermetallic composite.

Abstract: An environmentally resistant coating comprising silicon, titanium, chromium, and a balance of niobium and molybdenum for turbine components formed from molybdenum silicide-based composites. The turbine component may further include a thermal barrier coating disposed upon an outer surface of the environmentally resistant coating comprising zirconia, stabilized zirconia, zircon, mullite, and combinations thereof. The molybdenum silicide-based composite turbine component coated with the environmentally resistant coating and thermal barrier coating is resistant to oxidation at temperatures in the range from about 2000° F. to about 2600° F. and to pesting at temperatures in the range from about 1000° F. to about 1800° F.