挤压态镍基粉末高温合金微观组织分析  

Microstructure analysis on extruded nickel-based powder superalloy

作　　者：宋晓俊 王超渊 汪煜 周磊 邹金文 Song Xiaojun;Wang Chaoyuan;Wang Yu;Zhou Lei;Zou Jinwen(Key Laboratory of Advanced High Temperature Structural Materials,Beijing Institute of Aeronautical Materials,Beijing 100095,China)

机构地区：[1]中国航发北京航空材料研究院,先进高温结构材料重点实验室,北京100095

出　　处：《锻压技术》2020年第12期195-202,共8页Forging & Stamping Technology

摘　　要：镍基粉末高温合金在挤压比为4∶1、挤压速度为20 mm·s^-1和变形温度为1050~1180℃的条件下进行挤压变形,将挤压后的试样在1000~1100℃条件下保温10~120 min,分析挤压态镍基粉末高温合金及其热处理过程中微观组织及再结晶晶粒的形核及长大。实验结果表明:挤压态镍基粉末高温合金中存在两种类型的γ′相,大尺寸γ′相多分布于晶界上,尺寸约为1~2μm,小尺寸γ′相多分布于晶粒内部,尺寸约为200 nm,呈弥散状态分布;经过1080和1100℃保温10,30,60和120 min的热处理后,大尺寸γ′相的含量和尺寸均变化不大,小尺寸γ′相基本完全溶解;热挤压变形过程中形成的位错胞,在加热过程中位错重新排列并对消形成亚晶,进而形成再结晶核心。再结晶核心通过应变能和界面能的驱动实现长大,由于合金中大尺寸γ′相的存在,在再结晶形核后的长大过程中,其晶界的迁移受γ′相的钉扎作用,抑制了晶粒长大,使合金晶粒组织具有良好的热稳定性。The nickel-based powder superalloy was extruded in the condition of the extrusion ratio of 4∶1,the extrusion speed of 20 mm·s^-1 and the deformation temperature of 1050-1180℃,and the extruded samples were kept at 1000-1100℃for 10-120 min to analyze the microstructure and recrystallized grain nucleation and growth of extruded nickel-based powder superalloy and its heat treatment process.The results show that there are two types ofγ′phases in extruded nickel-based powder superalloy.The large-sizedγ′phases are mostly distributed on the grain boundary with a size of about 1-2μm,and the small-sizedγ′phases size are mostly distributed inside the grains with a size of about 200 nm which is distributed in a dispersed state.After heat treatment at 1080 and 1100℃for 10,30,60 and 120 min,the content and size of the large-sizeγ′phase do not change much,and the small-sizedγ′phase is almost completely dissolved.Furthermore,the dislocation cells formed in the process of hot extrusion deformation rearrange and cancel to form subgrains during the heating process,and then form the recrystallized core,and the growth of recrystallized core is driven by strain energy and interface energy.Due to the existence of the large-sizedγ′phase in the alloy,the migration of grain boundary is affected by the pinning ofγ′phase during the growth process after recrystallization and nucleation to suppress the growth of grains,which make the alloy grain structure have good thermal stability.

关 键 词：挤压态镍基粉末高温合金 微观组织 再结晶 γ′相 亚晶 位错胞 

分 类 号：TG430.10[金属学及工艺—焊接]