Grain size control of commercial wrought Mg-Al-Zn alloys utilizing dynamicrecrystallization

Dynamic recrystallization (DRX) behavior was systematically examined in two commercial Mg-Al-Zn alloys in order to clarify the relationship between de formation conditions and the resulting microstructure. The materials were d eformed by upset forging at temperatures ranging from 473 to 673 K at an in itial strain rate of 3.3 x 10(-2) s(-1). Grain refinement was observed duri ng deformation. It was found that the dynamically recrystallized grain size decreases with an increasing Zener-Hollomon parameter and/or a decreasing initial grain size. A phenomenological constitutive equation was developed in order to provide a guideline for the control of the grain size of hot de formed AZ61 alloy.