(中国科学院 金属研究所，沈阳 110016)
摘 要: 研究了不同时效热处理后挤压态γ-TiAl合金在高温期间显微组织的稳定性。结果表明：在1 330 ℃将Ti-47Al-2Cr-2Nb-0.15B合金挤压得到近片层组织，将α单相区热处理后得到全片层组织，在700~1 000 ℃停留不同时间后进行时效处理，从平行挤压方向上观察，在全片层晶界处出现细小γ晶粒，随着时效时间的延长，γ晶粒增大，其体积分数增加；全片层晶粒晶界处的非连续界面处首先发生不连续粗化，最终转变为拉长的γ晶粒，然后层片晶团内部各片层之间的连续界面处发生连续粗化，具有小曲率的薄α2片层开始以逐步变薄的方式断开和溶解，γ片层得到粗化。
关键字: TiAl；时效热处理；显微组织；片层
α extruded TiAl alloy
（Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China）
Abstract:The stability of the microstructure of extruded γ-TiAl alloy in high temperature was studied after different aged-heat treatment. The results show that Ti-47Al-2Cr-2Nb-0.15B alloy is extruded in 1 330 ℃ and the deformed near full lamellar (NFL) microstructure is obtained. Full lamellar (FL) microstructure forms after single α phase is heat treated. Observing from parallel extruding direction, the fine γ grain appears in FL grain boundary after being held at 700− 1 000 ℃ for different times. As the aged-time prolongs, the γ grain grows up and the volume fraction of γ grain increases. Discontinuous coarsening happens in the discontinuous boundary of FL grains firstly, which transforms the extended γ grain eventually, and then the continuous interface thickens continuously among lamellars in inner grain, the thin and small curvature α2 lamellar starts to disconnect and melt and the γ lamellar is thickened.
Key words: TiAl; aged-heat treatment; microstructure; lamellar
