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采用分离式Hopkinson Bar技术和一种新型的中断动态试验方法对TC6钛合金进行了动态压缩试验,通过光学显微镜、扫描电子显微镜分析了TC6钛合金变形到不同应变量时所产生绝热剪切带的微观形貌,通过与宏观力学响应相对应,研究了TC6钛合金在动态压缩变形中,绝热剪切带的形成过程及造成应力快速下降的原因。结果表明:在高应变率下,材料绝热剪切带的形成是一个由萌生、扩展、完全发展组成的过程;在应变率为2.5×10~3s~(-1)的动态压缩过程中,“应力塌陷”现象是由于材料内产生了大于一定尺寸的微裂纹所致。
The dynamic compression test of TC6 titanium alloy was carried out by using the separated Hopkinson Bar technology and a new type of discontinuous dynamic test. The thermal shear bands of TC6 titanium alloy were analyzed by optical microscope and scanning electron microscope The micro-topography and the macroscopic mechanical response were used to study the formation process of adiabatic shear band and the reason of rapid decrease of stress in TC6 titanium alloy under dynamic compression deformation. The results show that the formation of adiabatic shear band is a process of initiation, expansion and complete development at high strain rate. In the dynamic compression process with a strain rate of 2.5 × 10 ~ 3s -1, The “stress collapse” phenomenon is due to the generation of microcracks larger than a certain size in the material.