Influence of the grain size on the strain rate sensitivity in an Mg-Al-Zn alloy at moderate temperatures

The effect of grain size on the strain rate sensitivity (SRS) of the magnesium alloy Mg-3 wt.%Al-0.75 wt.%Zn has been investigated. It is shown that the SRS increases strongly for decreasing grain size below 15 pm. There is a close correlation between the SRS and the work hardening behavior. The current models are not capable of explaining this grain size dependence. The experimental results give a clue about an increasing contribution of grain boundary sliding to deformation. (c) 2006 Acta Materialia, Inc. Published by Elsevier Ltd. All rights reserved.