Zhang Jun, Wang Yang, Zhang Bin, Huang Hanjun, Chen Junhong, Wang Peng
Institute of Systems Engineering, China Academy of Engineering Physics, Mianyang 621999, China.
Department of Modern Mechanics, CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China, Hefei 230027, China.
Materials (Basel). 2018 Sep 2;11(9):1591. doi: 10.3390/ma11091591.
The complex deformation usually involves wide strain-rate change. However, few efforts have been devoted to investigate the effect of strain rate history on the tensile behavior of α + β titanium alloy. In present paper, tensile tests of Ti-6.6Al-3.3Mo-1.8Zr-0.29Si alloy were carried out under both constant and variable strain-rate conditions within the region from 10~500 s. A single stress pulse experimental technique was utilized to conduct the recovery tests. The strain-rate history effect was examined. It is found that the flow stress is independent on the strain rate history, though the alloy exhibits obvious positive strain rate sensitivity. The Taylor-Quinney coefficient of the plastic work converted to heat is proved as 0.9 at high strain rates. The cavitation fracture mechanism is revealed by microstructural observation over the full range explored. In basis of the experimental results and other pulished literatures, empirical Khan-Huang-Liang constitutive model was suitably modified to account for the strain-rate dependent behavior. Good agreement is achieved between the modeling prediction results and experimental data.
复杂变形通常涉及较大的应变速率变化。然而，很少有人致力于研究应变速率历史对α + β钛合金拉伸行为的影响。在本文中，对Ti-6.6Al-3.3Mo-1.8Zr-0.29Si合金在10~500 s范围内的恒定和可变应变速率条件下进行了拉伸试验。采用单应力脉冲实验技术进行了回复试验。研究了应变速率历史效应。结果发现，尽管该合金表现出明显的正应变速率敏感性，但流变应力与应变速率历史无关。在高应变速率下，塑性功转化为热的泰勒-奎尼系数被证明为0.9。通过在所探索的全范围内进行微观结构观察，揭示了空化断裂机制。基于实验结果和其他已发表的文献，对经验性的汗-黄-梁本构模型进行了适当修改，以考虑应变速率相关行为。建模预测结果与实验数据之间取得了良好的一致性。
