铸造高铌TiAl合金的热变形能力研究

Hot Deformability of Cast High Nb Containing TiAl Alloy

在Gleeble-1500热模拟试验机上对高铌TiAl合金进行等温热压缩试验，研究其热压缩变形的流变应力行为。压缩试验的形变温度为900～1250℃，形变速率为5×10^-4～1s^-1，工程压缩应变为50％和80％。用Zenner-Hollomon参数的指数函数能较好地描述该合金高温变形时的流变应力行为；所获得的峰值应力热变形方程为σp=197．61n{（Z／9．59×10^15）^0.285＋[（Z／9．59×10^15）^0.570＋1]^1/2}，其变形激活能为（497±49）kJ／mol。本研究还给出了铸造高铌TiAI合金热变形抗力图。

The hot compressive deformation behaviour of high Nb containing TiAI alloy was investigated in the temperature range of 900-1250 ℃, at the strain rate range of 5×10^-4-1s^-1 and the engineering strain range of 50%-80% on Gleeble-1500 hot simulator. The flow stress behaviour of high Nb containing TiAI alloy can be represented by a Zener-Hollomon parameter in the exponent style equation. The regressed expression is σp=197.61n{（Z/9.59×10^15）^0.285＋[（Z/9.59×10^15）^0.570＋1]^1/2}. The hot deformation activation energy of high Nb containing TiAl alloy during hot deformation is （497±49）10/mol. The hot deformability map of cast high Nb containing TiAl alloy was given in this paper.