TC4钛合金在不同温度下的剪压缩失效

利用Fallwerk试验装置,在高应变率(102s-1)下,采用动态剪压缩试验研究TC4钛合金不同温度下的剪压缩失效现象。通过试验发现:相同温度下,流变应力随应变的增大不断增加,到达峰值后发生应力塌陷,即剪切失效;相同应变下,温度越高,材料的屈服强度和流变应力均明显下降,且峰值应力向应变增大的方向移动,即塑性变形能力逐渐加强;温度升高,材料的剪切失效能力减弱,在673 K至873 K温度区间内存在一个温度极限值。在该极限值以下,材料易发生剪切失效。同时,根据试验数据拟合了峰值应力和最大塑性应变与温度的曲线方程,为钛合金的研究提供了理论依据。

The Shear Compression Failure of TC4 Titanium Alloy at Different Temperatures

Under the high strain rate(102 s―1) condition,the shear compression failure of TC4 titanium alloy at different temperatures is researched using Fallwerk device and dynamic shear compression test method.It is found that flow stress increases with the augmentation of strain increasing at the same temperature and the stress collapse,namely shear failure will happen when the stress reaches peak value.The yield strength and flow stress are obviously decreasing with the rising of temperature at the same strain.The peak stress moves towards the direction of strain increase,which is gradual strengthening of plastic deformation capacity.At the same time,shear failure ability is weakened with the rising of temperature.A temperature ultimate value exists in the range of 673 K to 873 K.Under this value,shear failure will happen easily,and above this value,shear failure won't happen.Finally,the curve equations of peak stress and maximum plastic strain against temperature are fitted using experimental data.It can provide theoretical basis for research of titanium alloy.