Effect of preliminary strain hardening on the flow stress of titanium and a titanium alloy during shock compression

摘要

The effect of preliminary strain hardening of VT1-0 titanium and a Ti-6 wt % Al-4 wt % V alloy on their mechanical properties under quasi-static and high-rate (> 10(5) s(-1)) loading is studied. Preliminary hardening is accomplished using equal-channel angular pressing (which results in a significant decrease in the grain size and a twofold increase in the quasi-static yield strength) and shock waves. High-rate deformation is attained via shock-wave loading of samples. The experimental results show that structural defects weaken the dependence of the yield strength on the strain rate. The difference in the rate dependences can be so high that the effect of these defects on the flow stress can change sign when going from quasi-static to high-rate loading. (C) 2005 Pleiades Publishing, Inc.