及其拉伸性能
(中国科学院 金属研究所，沈阳 110016)
摘 要: 采用感应熔炼气体雾化法制备Ti-47Al-2Cr-2Nb-0.2W-0.15B预合金粉末，对预合金粉末进行表征，通过热等静压工艺制备TiAl基合金坯料。应用包套叠轧的方法轧制出TiAl基合金板材，对轧制的TiAl基合金板材进行不同相区的热处理，分别得到双态组织和全片层组织，对热处理后的TiAl基合金进行拉伸性能测试。结果表明：TiAl基合金的预合金粉末主要由α2相和少量γ相组成，热等静压致密化处理后的板坯组织细小均匀。拉伸实验表明，双态和全片层组织的TiAl基合金板材在高于700 ℃时，其塑性大幅提高；双态组织TiAl基合金板材的断裂形式主要以韧性断裂为主，而全片层TiAl基合金板材的断裂形式仍为脆性断裂。
关键字: 粉末冶金；TiAl基合金；热处理；拉伸性能
Ti-47Al-2Cr-2Nb-0.2W-0.15B alloy sheets
（Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China）
Abstract:The Ti-47Al-2Cr-2Nb-0.2W-0.15B prealloyed powder was fabricated by electrode induction melting gas atomization technical, the pre-alloyed powder was characterized. The compacts of the alloy were hot isostatically pressed and pack rolled, and then heat treated at different temperatures in order to obtain different microstructures. The tensile tests were carried out on the specimens machined from the sheets. The results indicate that the pre-alloyed powder consists of α2 phase and a slight of γ phase, after hot isostatic pressing treatment, the microstructure is fine and homogenous. The elongations of TiAl alloy sheet with duplex significantly increases at the temperatures higher than 700 ℃, the same mechanical phenomenon also happens in the TiAl alloy sheets with full-lamellar microstructure. At the temperature higher than 700 ℃, the TiAl alloy sheets with duplex microstructure demonstrates ductile fracture. Although the TiAl alloy sheets with full-lamellar microstructure exhibit high elongation in the tensile test, the brittle fracture occurs.
Key words: powder metallurgy; TiAl based alloy; heat treatment; tensile property
