Superplastic behavior at high strain rate of rapidly solidified powder metallurgy AlLi alloy

Abstract

A number of studies which reveal that superplasticity can sometimes occur at an extremely high strain rate (> 10[sup [minus]1]s[sup [minus]1]) have been reported in several classes of materials, including metal-matrix composites and mechanically-alloyed (MA) materials. Since multiphase aluminum alloys processed by rapid solidification techniques can have fine stable grains, the interest in the superplastic behavior of these alloys increased sharply. Some tests indicated that rapid solidification processed (RSP) aluminum alloys can exhibit superplastic behavior, but nearly all optimum strain rate in above experiments are relatively low. In this paper, high strain rate superplasticity of rapid solidification processed Al-Li alloy has been researched. It is demonstrated that a maximum elongation of 250% is obtained at a high strain rate of 1.4 [times] 10[sup [minus]1]s[sup [minus]1] at 570 C, which is above the solidus temperature of 562 C.