中文摘要：

FGH96高温合金的再结晶主要包括孕育期、形核期和晶核长大期。再结晶形核与长大对温度非常敏感：当变形量较小时,在1050℃充分形核,在1080℃再结晶晶核等轴化过程稳定,能够得到均匀细小的等轴晶,而当温度高于1110℃时,再结晶等轴晶粒显著长大;随着变形量的增大,获得细晶粒的温度由1110℃降低到1080℃左右。促进形核、抑制晶粒长大均有利于晶粒细化。另外,再结晶优先在原始颗粒边界发生,当变形不充分时,内部残留未再结晶区,得到不完全再结晶组织,即＂项链＂组织。同时,这种组织也是粉末冶金材料晶粒细化过程中必然存在的中间态特征组织,随着变形方向的增加、累积变形量的增大,原始颗粒中心区域能够发生再结晶,＂项链＂组织也逐渐转化成等轴细晶组织。

英文摘要：

The recrystallization of powder metallurgical superalloy FGH96 undergoes three characteristic periods, viz., incubation, nucleation and growth. The recrystallization behavior is sensitive to annealing temperature. When the temperature is 1050 ℃, there is lots of nucleation at the previous particle boundaries. The nucleation grows up and the fine equiaxed grains are obtained when the temperature is 1080 ℃. However, the equiaxed grains would significantly get coarse when the temperature is 1110 ℃. Recrystallization usually takes place at previous particle boundaries during hot deformation process. When the deformation is not enough, a typically incomplete recrystallization microstructure, named the ＂necklace microstructure＂, will be obtained. The ＂necklace microstructure＂ has fine equiaxed grains inlayed in non-equiaxed coarse grains surrounding. Meanwhile, it is also the intermediate microstructure during the refinement processing of the powder metallurgical materials. Both the severe total deformation and multiple deformation direction are favorable for grain refinement.