NICKEL BASE SUPERALLOY IMPROVED IN CRACK ELONGATION RESISTANCE, OBJECT CONTAINING THE SAME AND THEIR PRODUCTION

摘要

PROBLEM TO BE SOLVED: To produce a high strength Ni base superalloy excellent in durability to the elongation of cracks under the condition in which hydrogen brittleness is easy to generate by subjecting an ingot of an Ni base alloy contg. Cr, Co, Mo, W, Fe and other specified elements to heating and cooling under specified temp. conditions. ;SOLUTION: A gamma prime strengthened Ni base alloy contg. specified amounts of C, Cr, Co, Mo, W, Ti, Al, Ta, Hf, Fe, Re and Nb, and the balance Ni is heated to melt gamma-gamma prime eutectic islands and script type carbides, which is gradually cooled to about 1,168°C and is furthermore rapidly cooled to 538°C in a vacuum. The high strength nickel base superalloy having a structure with a microstructure substantially contg. no script type carbides, gamma-gamma prime eutectic islands and fine pores, and in which the microstructure substantially contains regularly present plural big gamma prime precipitates which are formed into barriers and a fine cube type gamma prime precipitate continuous layer surrounding the above is produced.;COPYRIGHT: (C)1997,JPO