Abstract: The present invention relates to an improved single crystal nickel base superalloy and a process for making same. The single crystal nickel base superalloy has a composition comprising 3 to 12 wt % chromium, up to 3 wt % molybdenum, 3 to 10 wt % tungsten, up to 5 wt % rhenium, 6 to 12 wt % tantalum, 4 to 7 wt % aluminum, up to 15 wt % cobalt, up to 0.05 wt % carbon, up to 0.02 wt % boron, up to 0.1 wt % zirconium, up to 0.8 wt % hafnium, up to 2.0 wt % niobium, up to 1.0 wt % vanadium, up to 0.7 wt % titanium, up to 10 wt % of at least one element selected from the group consisting of ruthenium, rhodium, palladium, osmium, iridium, platinum, and mixtures thereof, and the balance essentially nickel. The single crystal nickel base superalloy has a microstructure which is pore-free and eutectic ?–?? free and which has a gamma prime morphology with a bimodal ?? distribution.

Abstract: The present invention relates to an improved single crystal nickel base superalloy and a process for making same. The single crystal nickel base superalloy has a composition comprising 3 to 12 wt % chromium, up to 3 wt % molybdenum, 3 to 10 wt % tungsten, up to 5 wt % rhenium, 6 to 12 wt % tantalum, 4 to 7 wt % aluminum, up to 15 wt % cobalt, up to 0.05 wt % carbon, up to 0.02 wt % boron, up to 0.1 wt % zirconium, up to 0.8 wt % hafnium, up to 2.0 wt % niobium, up to 1.0 wt % vanadium, up to 0.7 wt % titanium, up to 10 wt % of at least one element selected from the group consisting of ruthenium, rhodium, palladium, osmium, iridium, platinum, and mixtures thereof, and the balance essentially nickel. The single crystal nickel base superalloy has a microstructure which is pore-free and eutectic &ggr;-&ggr;′ free and which has a gamma prime morphology with a bimodal &ggr;′ distribution.

Abstract: Compositional requirements and processing improvements are disclosed which improve the hydrogen embrittlement resistance and the fatigue resistance in air of nickel base single crystal articles. The compositional requirements enlarge the difference between the &ggr;′ solvus temperature and the incipient melting temperature, thus enabling the solution of &ggr;/&ggr;′ eutectic islands without causing incipient melting, while hot isostatic pressing and careful melt practice eliminate porosity and carbides, borides and nitrides, all of which act as crack initiation sites.

Abstract: A nickel base superalloy, having either columnar or equiaxed grain structure, which has significantly improved resistance to hydrogen embrittlement, and to fatigue in air. The material is processed so as to be essentially free of script type carbides, .gamma./.gamma.' eutectic islands and porosity. The processing includes heat treating above the .gamma.' solvus temperature to solution the script type carbides and eutectic islands, followed by HIP to eliminate the porosity.

Abstract: A nickel base superalloy, having either columnar or equiaxed grain structure, which has significantly improved resistance to hydrogen embrittlement, and to fatigue in air is disclosed. The superalloy consists essentially of, in weight percent, about 0.006-0.17 carbon, about 6.0-22.0 chromium, up to about 17.0 cobalt, up to about 9.0 molybdenum, up to about 12.5 tungsten, up to about 5.0 titanium, up to about 6.7 aluminum, up to about 4.5 tantalum, up to about 2.5 hafnium, up to about 18.5 iron, up to about 3.25 rhenium, up to about 1.25 columbium, remainder nickel. The microstructure of the superalloy consists essentially of a plurality of fine, discrete carbide particles, .gamma.' precipitates in a .gamma. matrix, and is essentially free of script carbides, .gamma./.gamma.' eutectic islands and porosity.

Abstract: The present invention relates to a method for making a gamma prime precipitation strengthened nickel base alloy having an improved resistance to hydrogen embrittlement, particularly crack propagation. The alloy is cast, heat treated to dissolve substantially all the gamma-gamma prime eutectic islands and script carbides without causing incipient melting, cooled to below 1000.degree. C., HIP'ed to eliminate porosity, precipitation treated and aged. The alloy has a microstructure which is essentially free of script carbides, gamma-gamma prime eutectic islands and porosity. The microstructure further includes a plurality of regularly occurring large barrier gamma prime precipitates and a continuous field of fine cuboidal gamma prime precipitates surrounding the large barrier gamma prime precipitates.

Abstract: A repaired nickel-based superalloy substrate that has applied thereon a nickel-based polycrystalline repair alloy comprising 0.03-2.5 weight % hafnium, 0.003-0.32% boron, 0.02-0.16% yttrium and 0.007-0.35% zirconium. The present invention further provides a repaired single crystal alloy substrate that has applied thereon a repair alloy wherein the repair alloy's composition is similar to or the same as the single crystal alloy composition except that the repair alloy additionally comprises at least one grain boundary strengthener element and at least one element that enhances oxidation resistance.

Abstract: The present invention relates to a heat treated, gamma prime precipitation strengthened nickel base alloy having an improved resistance to hydrogen embrittlement, particularly crack propagation. The alloy has a microstructure which is essentially free of script carbides, gamma--gamma prime eutectic islands and porosity. The microstructure further includes a plurality of regularly occurring large barrier gamma prime precipitates and a continuous field of fine cuboidal gamma prime precipitates surrounding the large barrier gamma prime precipitates.

Abstract: Superalloy castings having large variations in section thickness are heat treated using a cyclic stress relief procedure, with the temperature being cycled between about 50.degree. F. (28.degree. C.) and 150.degree. F. (83.degree. C.) below the second phase particle solvus temperature, to relieve the residual stresses incurred during cooling within the mold following casting, followed by a solution cycle at a temperature about 25.degree. F. (14.degree. C.) below the second phase particle solvus temperature to dissolve some or all of the second phase particles.

Abstract: An abrasive, wear resistant layer is applied to the tip surface of a superalloy gas turbine blade by high temperature sintering operation which produces a high strength bond between the layer and the blade, minimizes gamma prime phase growth, and prevents recrystallization in the blade. Important features of the invention include the use of an inductively heated graphite susceptor to heat the blade, and a refractory metal shield which surrounds the airfoil and root portions of the blade while leaving the tip portion exposed to the heat source.