| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of forming a component from aγ' precipitation-strengthened nickel-base superalloy so that, following a supersolvus heat treatment the component characterized by a uniformly-sized grain microstructure is formed. SOLUTION: The method includes forming a billet having a sufficiently fine grain size to achieve superplasticity of the superalloy during a subsequent working step. The billet is then worked at a temperature below theγ' solvus temperature of the superalloy so as to form a worked article wherein the billet is worked so as to maintain strain rates above a lower strain rate limit to control average grain size and below an upper strain rate limit to avoid critical grain growth. Thereafter, the worked article is heat treated at a temperature above theγ' solvus temperature of the superalloy for a duration sufficient to uniformly coarsen the grains of the worked article, after which the worked article is cooled at a rate sufficient to reprecipitateγ' within the worked article. COPYRIGHT: (C)2008,JPO&INPIT |
