Deformation Mechanisms and High Strain Rate Properties of Magnesium (Mg) and Mg Alloys

Abstract

Abstract : This report summarizes research at the Johns Hopkins University Center for Advanced Metallic and Ceramic Systems on lightweight magnesium (Mg) and Mg alloys, under the sponsorship of the U.S. Army Research Laboratory (ARL) Materials Center of Excellence (MCOE) during 2007-2010. In collaboration with ARL, extensive studies have been conducted on the fundamental deformation mechanisms of pure Mg and the mechanical properties at high strain rate of ultrafine-grained Mg alloys. Atomistic simulations, transmission electron microscopy, and Kolsky bar testing have been performed to investigate the deformation mechanisms of Mg and Mg alloys. Newly uncovered mechanisms of pyramidal slip, {1011} 1012 twinning and {1012} 1011 twinning, were observed for hexagonal close-packed Mg. High strain rate properties of Mg alloys with submicron grain sizes were also studied.