An internal variable approach to the superplastic deformation of AZ31 magnesium alloy

The superplastic deformation behavior and microstructural evolution of a fine-grained AZ31 magnesium alloy have been investigated within the framework of an internal variable theory. A series of tensile and load relaxation tests were conducted first at the various temperatures and strain rates. The largest elongation of 426 % and the characteristic sigmoidal curves for the log flow stress vs. log strain rate curves were obtained. The microstructure observation revealed that dynamic recrystallization (DRX) and grain boundary sliding (GBS) occurred during superplastic deformation. The deformation behavior of AZ31 alloy could be described well by using the internal variable theory.