Solute segregation assisted superplasticity in a low-alloyed Mg-Zn-Ca-Sn-Mn alloy

In this study, we are pleased to report a low-alloyed Mg-1.0Zn-0.45Ca-0.35Sn-0.2Mn (wt. %) alloy sheet fabricated by hot rolling, showing superplastic deformation ability with tensile elongation of similar to 410%+/- 30% at 573 K and 1 x 10(-3) s(-1). The superplasticity is co-dominated by grain boundaries sliding (GBS) and solute drag creep. Unlike high-alloyed Mg alloys with dispersed precipitates, this low-alloyed system keeps its fine-grained microstructure by the co-segregation of Zn and Ca atoms at grain boundaries (GBs) coupled with a few precipitates. Although the co-segregation of Zn and Ca atoms at GBs are not favored for GBS, the resulting superior thermostability is of great importance to achieve superplastic deformation. Thus, we put forward a new path in achieving superplasticity in low alloyed Mg alloys by using a complementary thermodynamic and kinetic stabilization approach.