Influence of the strain rate on deformation mechanisms of an AZ31 magnesium alloy

Abstract

The paper reports mechanical properties of magnesium alloy AZ31 deformed at low and high strain rates. Material was prepared using squeeze casting technology. Compression tests were performed at an initial strain rate of 8.3 × 10−5 s−1 at temperatures between room temperature and 300°C. Dynamic compression Hopkinson tests were carried out at room temperature with impact velocities ranging from 11.2 to 21.9 m s−1. Transmission electron microscopy investigations showed significant dislocation and twins densities. Results are discussed considering the importance of the activation volume determined in the stress relaxation tests obtained at the low strain rate and, quite separately, the importance of adiabatic shear banding at high strain rates.