Friction stir processing of QE22 magnesium alloy to achieve ultrafine-grained microstructure with enhanced room temperature ductility and texture weakening

In the current study, a cast magnesium silver rare earth (QE22) alloy was processed via multi-pass friction stir processing under the rapid cooling system with an objective to achieve ultrafine-grain microstructure. The friction stir processed QE22 alloy after two pass exhibited an excellent ductility of 24% along with adequate yield strength of 195 MPa at room temperature. This unique combination in the properties of QE22 alloy could be due to the integrated effect of grain refinement via friction stir processing and texture modification. The influence of rare earth element on the grain refinement, dynamic recrystallization and texture evolution of the friction stir processed QE22 samples have been studied and compared with the traditional Mg-Al-Zn alloy.