Abstract: A single crystal nickel-base superalloy is disclosed having an improved incipient melting temperature and oxidation resistance. The single crystal nickel-base alloy of this invention is characterized by specific addition of chromium, tungsten, aluminum and tantalum to produce an alloy having moderate high temperature strength and improved oxidation resistance and incipient melting temperature. The nominal composition of our new single crystal alloy (in weight percent) is 10-15% Cr, 0-4% Co, 6-8.5% W, 6-7% Al, 0-1% Ti, 2-6% Ta, and the balance nickel.

Abstract: Nickel base superalloy single crystal articles, preferably aircraft gas turbine blades and vanes, and a process for preparation thereof, wherein phase stability after extended elevated temperature exposure is enhanced by controlling the content of heavy refractory elements and gamma prime phase forming elements. The nominal alloy composition range in weight percent is 4-6 percent chromium, 8-12 percent cobalt, 1-2.5 percent molybdenum, 3-6 percent tungsten, 1.8-3.2 percent rhenium, 0-2.5 percent ruthenium, 5-6 percent aluminum, 0.5-1.5 percent titanium, 7-10 percent tantalum, 0.08-0.12 percent hafnium, balance nickel. The sum of the heavy refractory elements molybdenum plus tungsten plus rhenium is 8.4-10.4 percent, and the sum of the gamma prime forming elements aluminum plus titanium plus tantalum is 13.8-15.7 percent.

Abstract: Nickel base superalloys intended for use at low to moderate temperatures are provided with improved corrosion resistance by the addition of from 0.2 to 0.6% manganese. The manganese addition also improves the creep properties of the alloys. The manganese modified alloys are suited for use as elements in gas turbine engines for marine environments.

Abstract: Monocarbide reinforced nickel-base eutectic superalloys which are substantially phase stable and have improved high temperature stress-rupture strength with improved resistance to the formation of surface nucleated carbides are provided. These superalloys are especially suited for making unidirectionally solidified anisotropic metallic bodies in the form of vanes and rotating blades for aircraft gas turbine engines.

Abstract: The microstructural stability of nickel base alloys at high temperatures is nhanced by the addition of cobalt within the range of 10.0 to 14.9 weight percent for reducing the precipitation of the sigma phase in alloys with more than 12 weight percent chromium. The nickel-base alloys having cobalt addition in the range as set forth are characterized by an electron vacancy number within the range of 2.4 to 2.7 inclusive.

Abstract: A specific composition range and process sequence are described for the production of single crystal superalloy articles which have an exceptional combination of high temperature mechanical properties and resistance to oxidation and hot corrosion. The nominal composition in weight percent is 7.5% Cr, 5.0% Al, 1.0% Ti, 2.0% Mo, 4.0% W, 12.0% Ta, 5% Co, balance nickel. Material of this composition is cast and solidified in single crystal form and heat treated to produce an optimum microstructure.