【摘要】 以Ti₂AlNb合金板材为研究对象，基于变形温度为1 273～1 423 K、应变速率为0.001～10 s^-1范围内的等温恒应变速率热压缩实验，深入分析了变形参数和微观组织对应变速率敏感指数m和应变硬化指数n的影响。结果表明：Ti₂AlNb合金的流动应力随变形温度的升高和应变速率的降低而减小；Ti₂AlNb合金等温压缩过程中的峰值m为0.61，出现在1 323 K/0.001 s^-1；当变形温度为1 273～1 323 K时，m随应变速率的增大而减小，当变形温度为1 373～1 423 K时，m随应变速率的增大而增大；当应变速率为0.001 s^-1时，n随应变的增大呈现先减小后增大的趋势，而当应变速率为0.01～10 s^-1时，n却呈现先增大后减小的变化趋势；Ti₂AlNb合金应变硬化指数n值和应变速率敏感指数m值均随着晶粒尺寸的增大而减小；Ti₂AlNb合金板材较优的加工区间为1 273～1 323 K/0.001～0.01 s^-1以及1 373～1 423 K/0.1～1 s^-1。这对通过工艺优化组织，进而改进Ti₂AlNb合金板材的性能具有重要的理论意义和工程价值。更多还原

【Abstract】 The effects of deformation parameters and microstructure on the strain rate sensitivity m and strain hardening exponent n were analyzed in depth based on isothermal compression experiments of Ti₂AlNb alloy plates at the deformation temperatures of 1 273—1 423 K and the strain rates in the range of 0.001—10 s^-1. The results showed that the flow stress of Ti₂AlNb alloy decreases with the increasing deformation temperature and decreasing strain rate. The maximum m value of 0.61 occurred at 1 323 K and a strain rate of 0.001 s^-1 during the isothermal compression of Ti₂AlNb alloy. Moreover, the m value decreased with the increase of strain rate in the deformation temperature range of 1 273—1 323 K. On the contrary, the m value increased with the increase of strain rate in the deformation temperature range of 1 373—1 423 K. Furthermore, the n value decreased firstly and then increased with the increase of strain at the strain rate of 0.001 s^-1, but at the strain rate of 0.01—10 s^-1, the n value increased firstly and then decreased with the increase of strain. In addition. the strain hardening exponent and strain rate sensitivity of Ti₂AlNb alloy both decreased with the increase of grain size. Finally, the better processing windows of Ti₂AlNb alloy sheet were given as 1 273—1 323 K/0.001—0.01 s^-1 and 1 373—1 423 K/0.1—1 s^-1. This has important theoretical significance and engineering value for to improve the properties of Ti₂AlNb alloy sheet by optimizing the microstructure through the process.更多还原