ACCROISSEMENT THERMO-MECANIQUE DE LA RESISTANCE DES SUPERALLIAGES (

摘要

The superalloys are strengthened in a process involving both thermal and deformational treatments under controlled conditions. The method is particularly effective for the nickel-base superalloys of the gamma - gamma ' -type having a volume fraction of the gamma ' phase exceeding about 25 percent at room temperature, and for the superalloys precipitating the topologically close-packed phases such as the sigma phase. It relies on the establishment of a microstructure wherein the gamma ' phase is precipitated in a uniformly distributed array having an interparticle spacing not exceeding about 5 microns; warm working the alloy to effect an area reduction of at least 15 percent; and subjecting the alloy to a stabilization heat treatment. The strength increase is attributable to a particular thermally and mechanically stable array of microcrystalline imperfections thus established and, in those alloys precipitating the sigma phase, also by an altered sigma phase morphology.