采用Gleeble-1500试验机对经过挤压比为12开坯后的γ-TiAl合金在温度为900～1100℃、应变速率为0.01～1s<'-1>、变形量为70%等温恒应变速率下的热变形行为进行了研究,获得了变形条件范围内的流变应力数据,并利用Ze-ner-Hollomn参数和Arrhenius方程得出γ-TiAl合金的本构方程.结果表明:γ-TiAl合金在900℃,应变速率为1s<'-1>和0.1s<'-1>的条件下新生动态再结晶品粒较少,并且动态再结晶发生的热力学条件比一般高温合金更加苛刻.所获得的流变应力方程为σ=48.1(1nε+413.53×10<'3>/RT-28.37);其热变形激活能Q=413.53kJ/mol,为科学设计和有效控制γ-TiAl合金的锻造工艺提供了理论依据.%The hot compressive deformation behavior of extruded γ-TiAl alloy with a reduction of the cross section of 12:1 was investigated at 900-1100℃ and at strain rate 0. 01-1. 0s-1 and with 70% height reduction on Gleeble-1500 hot simulator. The effects of thermomechanical parameters on flow stress and dynamic recrystallization were analyzed. A constitutive relationship based on the Zener-Hollomn parameter and Arrhenius equation was proposed for γ-TiAl alloy. The result shows that the calculation results of the proposed model agree well with the experimental data. Therefore, the proposed model can lay foundation of quality control and process design for the secondary processing of γ-TiAl alloy.
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