Transition of superplastic and dislocation creep of duplex Mg-Li-Al-Zn alloy

In this study, temperature dependence of creep behavior in a duplex Mg-Li-Al-Zn alloy was investigated. Below 473 K, creep deformation in this alloy was primarily governed by the viscous motion of dislocations. In contrast, at temperatures above 493 K, dynamic recrystallization (DRX) occurred during creep deformation, leading to a remarkable elongation exceeding 500%. Consequently, the creep behavior of the duplex Mg-Li-Al-Zn alloy exhibits a transition from viscous glide-control creep at relatively low temperatures to DRX-control superplastic creep at relatively high temperatures. These creep deformation mechanisms were elucidated through analyses based on stress exponent, activation energy of creep, and dynamic microstructural evolution.