Achieving high strain rate superplasticity in an Al-Cu-Li alloy processed by thermo-mechanical processing

Abstract

In order to obtain high strain rate superplasticity, it is usually necessary to prepare fine-grained aluminum alloy by severe plastic deformation such as equal channel angular pressing. A traditional thermo-mechanical processing was exploited to prepare fine-grained Al-Cu-Li alloy with 3.1 μm grains. A maximum elongation of 1220% was obtained at a high strain rate of 1 × 10−2 s−1 and 490 °C. The high-stain rate superplasticity is attributed to the existence of stabilized fine grains and nano-scaled Al3Zr particles which inhibit the dynamic growth of grain. Furthermore, the calculated deformation activation energy and m values suggest that the grain boundary sliding mechanism is active.