Formation of ultrafine grains in magnesium alloy during dynamic extrusion at room temperature

Abstract Magnesium alloy is a class of lightweight structural materials with promise for many applications. Here, the authors report a significant grain refinement, high deformation twin density and obvious nanograined structures in magnesium alloy through a novel high strain rate plastic deformation method—dynamic extrusion. By using finite element simulation and transmission electron microscopy (TEM), the authors find that the stain rate during plastic deformation affects the microstructure evolution process, which results in the dynamic deformation mechanisms transition. The results are of interests not only for understanding the deformation mechanisms under dynamic plastic deformation but also for nanostructures formation of the magnesium alloy.