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 spe cimen deformed to a true strain of 0.6 was 9.1 mu m. The grain refinement w as attributed to dynamically continuous recrystallization during an initial stage of tensile test. Stabilization of subgrain boundaries by fine partic les and stimulation of continuous recrystallization by prior warm-deformati on were not needed to attain dynamically continuous recrystallization in th e Mg alloy. As a result of the grain refinement, the rolled Mg alloy exhibi ted superplastic behavior. (C) 2000 Elsevier Science S.A. All rights reserv ed.