Abstract: A nickel based single crystal superalloy comprising 7-9 wt % cobalt, 3.5-4.5 wt % chromium, 0-2.4 wt % molybdenum, 4-8 wt % tungsten, 3.5-6 wt % rhenium, 5-6.5 wt % aluminium, 6.5-8.5 wt % tantalum, 0-0.2 wt % hafnium and the balance nickel plus incidental impurities. The nickel based single crystal superalloy is suitable for use as a gas turbine engine turbine blade or turbine vane. It is of particular us on cooled turbine blades and turbine vanes which have ceramic thermal barrier coatings, because the superalloy is compatible with the ceramic thermal barrier coating to minimise spalling. The superalloy has better mechanical properties than other second-generation single crystal superalloys and has better creep strength and oxidation resistance.

Abstract: A nickel alloy composition, having particular utility for forming an oxidation resistant blade tip on a turbine blade, preferably has a composition substantially as defined by the nominal composition Cr 4.5 wt %; Al 6 wt %; Co 4 wt %; Ta 6 wt %; Re 4 wt %; Hf 0.15 wt %; C 0.05 wt %; Si 0.1 wt %; B 0.005 wt %; W 2 wt %; La 0.003-0.005 wt %; and Y 0.003 to 0.005 wt %; the remainder being nickel.

Abstract: A composition of matter comprising: 5 wt % to 8 wt % rhenium; 4 wt % to 8 wt % tantalum; 2 wt % to 5 wt % tungsten; 2 wt % to 5.5 wt % molybdenum; 2 wt % to 5 wt % chromium; 2 wt % to 6 wt % ruthenium; 2 wt % to 8 wt % cobalt; 5 wt % to 7 wt % aluminium; 0 wt % to 2 wt % titanium; 0 wt % to 0.5 wt % hafnium; and the balance nickel and incidental impurities.