Enhancement of strain-rate sensitivity and shear yield strength of a magnesium alloy processed by high-pressure torsion

Abstract

A Mg-Zn-Zr alloy was processed by high-pressure torsion for up to 2 turns at room temperature to produce significant grain refinement together with enhanced plasticity and strength. Measurements were performed to determine the strain-rate sensitivity, shear yield strength and activation volume as a function of the processing conditions. The results suggest there is a significant contribution from grain boundary sliding to the flow process and the onset of plasticity is associated with heterogeneous dislocation nucleation. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.