Microstructure features and superplasticity of extruded, rolled and spd-processed magnesium alloys: A short review

In this study, an overview of microstructure features such as grain size, grain structure, texture and its impact on strain rate sensitivity, strain hardening index, activation energy and thermal stability for achieving superplasticity of Mg alloys are presented. The deformation behavior under different strain rates and temperatures was also elaborated. For high elongation to fracture grain boundary sliding, grain boundary diffusion is the dominant deformation mechanism. In contrast, for low-temperature and high strain rate superplasticity, grain boundary sliding and solute drag creep mechanism or viscous glide dislocation followed by GBS are the dominant deformations. In addition, the results of different studies were compared, and optimal strain rate and temperature were diagnosed for achieving excellent high strain rate superplasticity.