In the present work, the hot deformation behavior of TB18 titanium alloy was investigated by isothermal hot compression tests with temperatures from 650 to 880°C and strain rates from 0.001 to 10 s⁻¹. The flow curves after friction and temperature correction show that the peak stress decreased with the temperature increase and the strain rate decrease. Three typical characteristics of flow behavior indicate the dynamic softening behavior during hot deformation. At a strain rate of 0.001∼0.01 s⁻¹, the flow stress continues to decrease as the strain rate increases after the flow stress reaches the peak stress; the flow softening mechanism is dynamic recovery and dynamic recrystallization at a lower temperature and dynamic recrystallization at a higher temperature. The discontinuous yielding phenomenon could be seen at a strain rate of 1 s⁻¹, dynamic recrystallization took place in the β single-phase zone, and flow localization bands were observed in the α + β two-phase zone. At a higher strain rate of 10 s⁻¹, the flow instabilities were referred to as the occurrence of flow localization by adiabatic heat. Constitutive equation considering the compensation of strain was also established, and the results show high accuracy to predict the flow stress with the correlation coefficient of 99.2% and the AARE of 6.1%, respectively.

中文翻译：

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TB18钛合金热变形的本构关系

在目前的工作中，通过等温热压缩试验研究了TB18钛合金的热变形行为，温度范围为650至880°C，应变速率为0.001至10 s ^-1。摩擦和温度校正后的流动曲线表明，峰值应力随着温度的升高而降低，应变率降低。流动行为的三个典型特征表明热变形过程中的动态软化行为。应变率为0.001〜0.01 s ^-1，在流变应力达到峰值应力后，随着应变率的增加，流变应力继续减小。流动软化机理是在较低温度下的动态恢复和动态再结晶，以及在较高温度下的动态再结晶。在1 s ^-1的应变速率下可以看到不连续的屈服现象，在β单相区发生动态再结晶，在α  +  β两相区观察到流动局部化带。在10 s ^-1的较高应变速率下，将流动不稳定性称为绝热引起的流动局部化。建立了考虑应变补偿的本构方程，结果表明流变应力预测的准确性较高，相关系数分别为99.2％和AARE为6.1％。