钛合金TC-4在高应变率下的动态本构关系

DYNAMIC PROPERTIES OF TC-4 TITANIUM UNDER HIGH STRAIN-RATE

利用分离式Hopkinson扭杆对钛合金TC-4进行了高应变率下动态剪切本构关系的实验研究。结果表明TC-4对应变率高度敏感,对应变率的敏感性随应变率的提高而增加。其动态应力应变关系呈线性强化形式。但动态强化模量随应变率的提高而略有减少。采用Malvern给出的过应力模式γ_p={exp[(1/α)(τ-f(γ))]-1}/b可以较好地描述TC-4的动态剪切本构关系。

The dynamic stress-strain relation of TC-4 titanium has been investigated experimentally under high strsin-rate by SHTB. It is showed that TC-4 is very sensitive to the strain-rate, and the sensitivity to the strain-rate increases with the rise of strain-rate. Although the dynamic hardening module decreases with the increase of strain-rate, the dynamic constitutive relation of TC-4 for a definite value of strain- rate can be illustrated in the linear hardening form. The experimental results arein good agreement with the Malverns over stress model γp={exe[(1/a)(τ-f(γ))]-l}/bBut this model can not be used to present the phenomenon which the dynamic hardening module decreases with the increase of strain-rate. This character is one of the important factors for the formation of adiabatic shear band.