摘要
TC18钛合金锻棒经900℃保温30 min空冷热处理后,在R/2和中心区域出现离散分布的"黑斑"。为此,对该棒材进行了化学成分和显微组织的分析。结果表明,"黑斑"不是成分偏析造成的,而是由于锻棒变形区域再结晶不完全,从900℃空冷时α相层片优先析出形成大量α/β界面所致。采用900℃保温30 min然后水冷的工艺,可以抑制α相层片析出,消除"黑斑"。
Forged bar of TC18 titanium alloy, after being heat treated by soaking at 900℃ for 30 rain and air cooling, was found to present the black freckles in the form of discretely distribute at a depth of R/2 and in core. For this reason the forged bar was subjected to chemical composition analysis and microstructure survey. The results indicate that the presence of the black freckle arises from preferred precipitation of lamellar α phase and, therefore, formation of a large amount of α-β interface due to incomplete recrystallization in deformed area of the forged bar during air cooling from 900 ℃, being independent from the segregation of chemical composition. The precipitation of lamellar α phase can be inhibited by soaking at 900 ℃ for 30 min and then water cooling instead of air cooling, thus eliminating the black freckle.
出处
《热处理》
CAS
2015年第5期49-54,共6页
Heat Treatment
关键词
TC18钛合金
黑斑
再结晶
水冷
TC18 titanium alloy
black freckle
recrystallization
water cooling
