Thermal stability of extension twins in Mg-3Al-1Zn rods

In the present study, Mg AZ31 rods were pre-twinned and subjected to different annealing treatments, with the aim to study the effect of annealing temperature, annealing time and pre-annealing on the thermal stability of the {10-12} twins. Our results show that, although the mobility of {10-12} twin boundaries (TBs) at 250 °C is quite limited, an annealing for 12 h can remove a part of twins. Enhancing annealing temperature greatly increases mobility of TBs and a longer annealing duration further reduces the amount of twins. However, a temperature higher than 375 °C is necessary to completely remove all the twins. The initial grain size in a range of 15-32 μm does not pose a great influence on the thermal stability of {10-12} twins. Recovery process by a pre-annealing at 200 °C for 6 h is not effective to enhance the thermal stability at higher temperature. During annealing, both the consumption of twins by matrix and that of matrix by twins take place, leading to hardly changed texture components in the annealed samples.