摘要
利用金相显微镜、扫描电镜、透射电镜等手段分析了GH720Li合金在两相区热压缩后的变形空冷态及退火态组织特征,探讨了该合金的静态再结晶机制.发现GH720Li合金在1100℃热变形及其后的空冷过程中主要发生回复现象,仅有少数再结晶晶粒可通过亚晶合并和亚晶长大的方式形核并长大;大量γ'相的限制使再结晶过程只能局限于单个或几个晶粒内.经不同时间退火后,再结晶可开动应变诱导晶界迁移及多个晶粒交界处的位错塞积区形核等机制,但一次γ'相的存在抑制了合金的整体再结晶进程.在基体变形及再结晶过程进行的同时,合金中一次γ'相也能够参与变形过程并发生一定程度的回复及再结晶现象.
The microstructure characteristics and recrystallization mechanism of GH720Li alloy deformed in the bi-model phase re-gion and then air cooled or annealed were investigated by metalloscopy, scanning electron microscopy and transmission electron micros-copy. It is found that the main softening mechanism after hot deformation at 1100℃ and air cooling is recovery and recrystallization oc-curs only in a limited portion of grains with the subgrain growth and merging mechanism due to a great content of gamma prime phase in the alloy. During the annealing process, the nucleation of static recrystallization may occur in dislocation pile-up areas located at the juncture of several grains or by strain-induced boundary migration （ SIBM） but the whole recrystallizing process is restrained by the retained percentage of primary gamma prime phase. It must be pointed that the retained primary gamma prime phase in GH720Li can also be somewhat deformed during hot working and then also softened to some extent by recovery and recrystallization during the annealing process.
出处
《北京科技大学学报》
EI
CAS
CSCD
北大核心
2014年第1期74-81,共8页
Journal of University of Science and Technology Beijing
关键词
高温合金
镍合金
显微结构
再结晶
回复
superalloys
nickel alloys
microstructure
recrystallization
recovery
