Realization of low-temperature superplasticity in Mg–Al–Zn alloy sheets processed by differential speed rolling

 AZ61 sheets processed by severe plastic deformation (SPD) using differential speed rolling (DSR) with a high speed ratio contained ultrafine grains 0.3–0.5 μm in size after a single rolling pass at 473 K for a thickness reduction ratio of 70%. The sheets exhibited good low-temperature superplasticity at 473 and 523 K, including a maximum elongation of 850% at 523 K and 3 × 10−4 s−1. The SPD-DSR process has great potential for use in the production of superplastic magnesium sheets.