Abstract: A method of repairing a component of a gas turbine engine that includes a metallic substrate, an existing aluminide coating, and a diffusion layer formed in the metallic substrate adjacent to the coating. The method includes removing at least a portion of the existing aluminide coating, removing material forming the diffusion layer, applying a new metallic layer to the metallic substrate, and applying a new aluminide coating over the new metallic layer to form a new diffusion layer in the new metallic layer. The new metallic layer is a substantially homogeneous material that is substantially similar in chemical composition to that of the metallic substrate, and the new metallic layer forms a structural layer having a thickness selected to provide a specified contour to the component.

Abstract: A method of repairing a component of a gas turbine engine that includes a metallic substrate, an existing coating, and a diffusion layer formed in the metallic substrate adjacent to the coating. The method includes removing at least a portion of the existing aluminide coating, removing material forming the diffusion layer, applying a new metallic layer to the metallic substrate, and applying a new aluminide coating over the new metallic layer to form a new diffusion layer in the new metallic layer. The new metallic layer is a substantially homogeneous material that is substantially similar in chemical composition to that of the metallic substrate, and the new metallic layer forms a structural layer having a thickness selected to provide a specified contour to the component.

Abstract: A process for producing a fine grain forged superalloy article having a high yield strength at intermediate temperatures. A preferred starting composition comprises, by weight, 15% Cr, 13.6% Co, 4.1% Mo, 4.6% Ti, 2.2% Al, 0.01% C, 0.007% B, 0.07% Zr, balance Ni. This material is forged at a temperature above the gamma prime solvus and at a true strain of at least 0.5. Alternately, the material may be forged below the gamma prime solvus temperature with intermediate super solvus anneals. The overaged material is then worked at a temperature below the gamma prime solvus. The resultant fine grain material is then heat treated or can be further isothermally forged prior to heat treatment to produce complex shapes.

Abstract: Heat treatments are described for improving the fatigue properties of superalloy articles, without adversely affecting other mechanical properties. The entire heat treatment process is performed below the gamma prime solvus temperature so that significant grain growth does not occur. The heat treatment cycle causes the formation of gamma prime particles in a controlled manner and morphology, first at the grain boundaries and then within the grains. The resultant microstructure possesses the benefits of a fine grain structure (improved resistance to fatigue crack initiation) and fine gamma prime particle size (improved resistance to crack growth).

Abstract: A process is described for converting a fine grain superalloy casting into a forging having mechanical properties equivalent to those resulting from powder metallurgy processing. Cast material is extruded and forged. A HIP treatment is employed to close porosity.

Abstract: Forging processes are described for cast superalloys. The forgeability of superalloy materials is improved by the development of overaged microstructure. The total forging process is usually performed in a series of steps with intervening heat treatments to reform the overaged microstructure.

Abstract: Methods for increasing the forgeability of cast superalloy materials are described. An extremely overaged microstructure is developed by solutionizing the material and slow cooling in the vicinity of the solvus temperature to cause a precipitation of extremely coarse gamma prime material. Subsequently the material can be isothermally forged.

Abstract: An interlayer for transient liquid phase diffusion bonding of the nickel, cobalt and iron alloys is provided between surfaces to be joined as a thin lamellar composite.

Abstract: An improved diffusion bonding fixture for holding workpiece surfaces in opposed contacting relation and exerting controlled pressure across the surfaces is disclosed. The fixture includes components having different thermal expansion characteristics which hold the workpiece surfaces together and generate pressure on the surfaces upon heating to the bonding temperature. The fixture also includes one or more pressure-controlling shim members disposed between the components of the fixture, the shim members being selectively and controllably deformed by the expanding components to control said bonding pressure at the desired value and to prevent unwanted distortion of the workpiece surfaces and fixture components. The fixture is especially useful in bonding workpiece surfaces of highly complex configurations, such as those associated with gas turbine blades, vanes and the like.

Abstract: In filling voids in or between metallic articles, as in the repair of cracks or other surface defects in castings, the void is filled with a powder mix which upon heat treatment fills the void. The filler powder mix is a blend of at least two distinct powder components and in terms of overall composition preferably corresponds to that of article being repaired. The components comprising the mix are selected to provide a transient liquid phase and isothermal resolidification of a portion of the mix at the temperature below the article melting point. A subsequent heat treatment is preferably utilized for homogenization.

Abstract: In filling voids in or between metallic articles, as in the repair of cracks or other surface defects in castings, the void is filled with a powder mix which upon heat treatment fills the void. The filler powder mix is a blend of at least two distinct powder components and in terms of overall composition preferably corresponds to that of article being repaired. The components comprising the mix are selected to provide a transient liquid phase and isothermal resolidification of a portion of the mix at the temperature below the article melting point. A subsequent heat treatment is preferably utilized for homogenization.