Abstract: A thermally stable, oxidation-resistant nickel-base alloy having good engineering properties for use in mechanical equipment operated at temperatures of up to 1600.degree. F. or higher is provided by maintaining the nickel content above 50% by weight and including as essential elements from about 12 to about 18% chromium, from about 8 to about 18% molybdenum and from about 0.005 to about 0.2% lanthanum by weight. Additional elements may be included in limited amounts provided that the average N.sub.v number of the alloy as defined herein is not substantially above about 2.5 and preferably is below about 2.4.

Abstract: A method is provided for producing ductile superalloys containing rare-earth metals, lanthanum and yttrium by melting the desired alloy composition by conventional melt practices, adding the rare-earth metals, lanthanum or yttrium to the molten composition, forming the alloy composition into solid electrodes, remelting the solid electrode by electroslag remelting techniques and casting the remelted alloy.

Abstract: A nickel-base cast alloy is provided having high retention of ductility and high thermal stability on aging coupled with low thermal expansion and good oxidation resistance. Such alloy has a composition in weight percent within the range molybdenum 13.7 to 15.5%, chromium 14.7 to 16.5%, carbon 0.02% max., boron up to 0.02%, manganese 0.3 to 1.0%, silicon 0.2 to 0.75%, cobalt 2.0% max., iron 3.0% max., tungsten 1.0% max., aluminum 0.1 to 0.5% and the balance nickel, said alloy having an N.sub.v number between 2.23 and 2.31.