Achieving high strain rate superplasticity in Mg-Y-Nd-Zr alloy processed by homogenization treatment and equal channel angular pressing

Homogenization treatment and equal channel angular pressing was applied to Mg-Y-Nd-Zr alloy cast ingot. Uniform grains with a grain size of similar to 1.5 mu m and spherical secondary-phase preferentially located at the grain boundaries were obtained. Excellent high-strain rate superplasticity of 860% and 960% was achieved at 500 degrees C, 1 x 10(-1) s(-1) and 475 degrees C, 2 x 10(-2) s(-1), respectively, for the first time such a highstrain rate superplasticity was achieved in magnesium alloys processed by ECAP. The maximum elongation of 1120% was achieved at 475 degrees C, 3 x 10(-3) s(-1). They were attributed to the thermal stability of uniform fine-grain microstructure and the coordination function of secondary-phase. (C) 2015 Elsevier B.V. All rights reserved.