Instantaneous strain rate sensitivity of wrought AZ31 magnesium alloy

The strain rate sensitivity evolution of a wrought AZ31 magnesium alloy was studied using strain rate jump (SRJ) testing technique. The strain rate jump tests were conducted in a wide temperature range of 200-550 degrees C under the base strain rates of 0.01 and 0.001 s(-1). The material exhibited the negligible strain-rate sensitivity at relatively low temperatures. However, the rate sensitivity of the alloy was found to be increased with increasing deformation temperature due to thermally activated nature of dislocation motion. In addition, the results indicated a rate sensitivity drop above 500 degrees C. This ascending/descending trend in positive rate sensitivity domain is systematically discussed relying on the main mechanisms operating in the related deformation conditions. Besides the effect of deformation temperature on the strain rate sensitivity, the influences of strain and strain rate are also properly addressed through this manuscript. (C) 2013 Elsevier Ltd. All rights reserved.