TC6钛合金剪切带临界应变及其扩展速度的实验测定

On critical strain corresponding to initiation and propagation velocity of adiabatic shear bands of TC6 titanium alloy

采用分离式霍普金森压杆技术和一种新型限位试验方法对TC6钛合金进行了动态压缩试验,使用光学显微镜、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钛合金圆柱试样中绝热剪切带刚萌生时对应的临界应变及绝热剪切带的扩展速率.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)时,TC6钛合金动态压缩时绝热剪切带萌生时对应的临界应变为0.126 9,其扩展速率大约为87 m/s.

Using the technology of split Hopkinson bar and a new method that can be used to interrupt test and obtain different amount of strain, a dynamic compression test has been done on TC6 titanium alloy.By associating microstructure of shear band under different amount of strain with mechanical response of material, critical strain corresponding to initiation and propagation velocity of adiabatic shear band have been studied.h shows that formation of adiabatic shear band of materials under high strain rate is a process composed of initiation, expansion and full development ; At present study, the critical strain corresponding to initiation of shear band of material tested is approximately 0.126 9 and the propagation velocity of shear band is approximately 87 m/s when strain rate is approximately 2.5×10^3s^-1.