FGH96合金晶粒长大规律的研究

Study on Grain Growth of P/M FGH96 Superalloy

对FGH96合金在热处理过程中晶粒长大规律进行了系统的研究。结果表明 ,γ′相对晶粒长大有显著阻碍作用 ,在低于γ′相固溶温度 (1 1 0 9℃ )热处理时 ,大量未溶解的γ′相使得晶粒长大缓慢 ;在高于γ′相固溶温度以上时 ,合金为单相奥氏体组织 ,晶粒随温度的升高快速长大。晶粒长大动力学表明 :在高于γ′相固溶温度以上时 ,晶粒生长指数随着热处理温度的升高而增加 ;在热处理温度为 1 1 35℃和1 1 5 0℃下的晶粒长大激活能为 2 93 4kJ mol,晶粒长大机理为自扩散过程控制机理 ,并建立了相应的晶粒长大动力学方程。

Grain growth behavior and its kinetics during heat-treating process of FGH96 superalloy have been investigated. The experimental results show that γ′ in the superalloy greatly restrain grain growth. Isothermal heat-treatment at temperature below γ′ dissolution leads to little variation of grain size and isothmal heat-treatment at temperature above γ′ dissolution leads to rapid grain growth for FGH superalloy. The grain growth kinetics at temperature above γ′ dissolution shows that grain growth exponentially increases with the increasing heat treating temperature. At the temperatures from 1135°C to 1150°C, the activation energy value for grain growth in FGH 96 superalloy is 293.4 kJ/mol, which means that the grain growth mechanism is self-diffusion-controlling process, and the grain growth kinetics equation are given.