Texture softening in a rare earth elements-containing AZ31 magnesium alloy during hot compression deformation

Abstract

The effect of rare element (RE) addition on the softening behavior of an AZ31 alloy was examined during hot compression. It was revealed that the RE-containing alloy (AZ31-1RE) exhibits a lower flow stress at deformation temperatures above the transition temperature of 220 °C, and higher flow stress below 220 °C, compared to the AZ31 alloy. To illustrate the textural effect on the flow stress behavior of the AZ31 and AZ31-1RE alloys, Taylor factor was computed from texture measurements. The results show that the AZ31-1RE alloy possesses a higher Taylor factor at temperatures below 220 °C such as 150 °C. However, the Taylor factor value was found to be lower for the AZ31-1RE alloy at the temperature of 300 °C, consistent with the observed flow stress behavior of both alloys above the transition temperature of 220 °C. No phase transformation was identified based on the differential scanning calorimetry (DSC) experiments in the temperature range of 100 °C–300 °C. There was also no sign of grain boundary sliding mechanism (GBS), as the obtained m-values for both alloys were significantly lower than 0.4. Therefore, the softening behavior at temperatures above the transition temperature was proposed to be associated with the effect of RE-element addition on texture softening.