Deformation-induced dissolution of long-period stacking ordered structures and its re-precipitation in a Mg-Gd-Zn-Mn alloy

Abstract

In this paper, the dissolution, refinement and re-precipitation of long period stacking order structure and solute-segregated stacking faults (LPSO structure/SFs) in an Mg-Gd-Zn-Mn alloy fabricated by hot extruding were studied. The results demonstrate that the refinement of LPSO structure/SFs was dominated by the misalignment mechanism and re-dissolution mechanism. Dislocation slips on the LPSO structure/SFs, as well as the rapid diffusion of solute atoms was responsible for the re-dissolution of LPSO structure/SFs. As the LPSO structure/SFs dissolved, a region with supersaturated solute atoms was formed and resulting in re-precipitation of SFs in continuous dynamically recrystallized grains. Finally, the evolution model of LPSO structure/SFs during continuous dynamic recrystallization was proposed.