Abstract: The invention relates to an alloy suitable for making single-crystal castings and to a casting made thereof. The alloy comprises, by weight percent, Chromium 10-16%, Cobalt 4-16%, Molybdenum 2-4%, Tungsten 0-2%, Tantalum 2-8%, the sum of ##EQU1## lying between 5 and 7%, Aluminium 4-6%, Titanium 1-4% the sum of ##EQU2## lying between 5 and 7%. Carbon 0.015-0.05%, Boron 0-0.01%, Zirconium 0-0.01%, the balance being nickel plus incidental impurities.

Abstract: An alloy composition intended for use in the form of a single crystal casting comprises a modified nickel-based superalloy. The alloy consists essentially of, by weight percent,7-13% Chromium,0-15% Cobalt,1.25-3% Titanium+1/2 Niobium,4.5-6.7% Aluminium,3-12% Tungsten,0-3.5% Molybdenum,0-5% Tantalum,0-2% Hafnium,0-1.5% Vanadium,0.015-0.05% Carbon,0-0.01% Boron,0-0.05% Zirconium,Balance essentially Nickel plus incidental impurities.The invention also contemplates a heat treatment for the alloy comprising initially heating to 1300.degree.-1320.degree. C. followed by cooling to room temperature and ageing the alloy at a temperature of about 870.degree. C. for 16 hours.

Abstract: An alloy is described which is suitable for the manufacture of castings which operate under high temperature conditions (such as nozzle guide vanes for gas turbine engines) but which can also be welded satisfactorily. The alloy comprises______________________________________ Chromium 14.5-16.5% Cobalt 9-11% Molybdenum 5.5-8% Aluminium 1.5-3% Titanium 1.5-3% Tantalum 0-1% Niobium 0-1% Boron 0.004-0.008% Iron 0-0.5% Manganese 0-0.4% Silicon 0-0.2% Nitrogen 0-0.5% Carbon 0.11-0.18% ______________________________________The balance being Nickel apart from incidental impurities.

Abstract: A blade or vane for a gas turbine has a cambered aerofoil made up of a plurality of single crystals of an alloy. Each crystal extends longitudinally of the aerofoil and has a predetermined three-dimensional orientation different from that of the other crystals such that it has an optimum value of a chosen property in directions longitudinal and transverse of the aerofoil.