Microstructural evolution and superplasticity of rolled Mg-9Al-1Zn

Microstructural evolution and superplasticity of a Mg-9Al-1Zn alloy rolled at 673 K were investigated at 573 K and 1.5 x 10(-3) s(-1). The grain size of the as-rolled Mg alloy was 39.5 mu m. However, the grain size of the specimen deformed to a true strain of 0.6 was 9.1 mu m. The grain refinement was attributed to dynamically continuous recrystallization during an initial stage of tensile test. Stabilization of subgrain boundaries by fine particles and stimulation of continuous recrystallization by prior warm-deformation were not needed to attain dynamically continuous recrystallization in the Mg alloy. As a result of the grain refinement, the rolled Mg alloy exhibited superplastic behavior. (C) 2000 Elsevier Science S.A. All rights reserved.