Achieving Superior Superplasticity in a Mg-6Al-Zn Plate via Multi-pass Submerged Friction Stir Processing

摘要

A large-scale Mg-6Al-Zn plate was prepared by multi-pass submerged friction stir processing(M-SFSP)and its superplastic deformation behavior was investigated.The maximum elongation of 467%,332%and 421%was attained for the samples oriented in the processing direction(PD),45°tilted toward the PD,and transverse direction(TD),respectively,when deformed at 623 K and a strain rate of 1×10^(−3) s^(−1).This was attributed to the homogeneous and fine-grained structure with mostly high-angle grain boundaries facilitating the prevalent deformation mechanism of grain boundary sliding,along with the weakened texture and dynamic recrystallization during hot deformation.