Abstract The hot deformation behavior of the as-cast Ti–48Al–2Cr–2Nb alloy was investigated by isothermal compression tests at deformation temperatures ranging from 1000 °C to 1200 °C, and strain rates from 0.001 s−1 to 0.1 s−1. The single peak stress features common to all flow curves indicate that DRX is the dominating softening mechanism. The calculated values of the hot deformation activation energy Q and stress index n are 296.5 kJ mol−1 and 3.97, respectively. Based on this, the Arrhenius type constitutive equation was successfully established. The DRX critical condition model and relationship among DRX volume fractions, deformation temperatures and strain rates were obtained to optimize the process. Combined with microstructure analysis, it's concluded that 1200 °C/0.01s−1 is the optimization parameter. Besides, both DDRX and CDRX were observed in the γ phase evolution. The deformation mechanism from the inter-grain dislocation motion to the grain boundary migration and grain rotation was discussed.

中文翻译：

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Ti-48Al-2Cr-2Nb合金在等温热变形过程中的动态再结晶行为

摘要 通过等温压缩试验研究了铸态 Ti-48Al-2Cr-2Nb 合金的热变形行为，变形温度范围为 1000 °C 至 1200 °C，应变速率为 0.001 s-1 至 0.1 s-1 . 所有流动曲线共有的单峰应力特征表明 DRX 是主要的软化机制。热变形活化能 Q 和应力指数 n 的计算值分别为 296.5 kJ mol-1 和 3.97。在此基础上，成功建立了Arrhenius型本构方程。获得了DRX临界条件模型以及DRX体积分数、变形温度和应变率之间的关系以优化工艺。结合微观结构分析，得出1200°C/0.01s-1为优化参数的结论。除了，在γ相演化中观察到DDRX和CDRX。讨论了从晶间位错运动到晶界迁移和晶粒旋转的变形机制。