Superplasticity of Mg–Zn–Y alloy containing quasicrystal phase processed by equal channel angular pressing

Abstract: Equal channel angular pressing (ECAP) has been conducted on as-cast Mg–4.3 wt.%Zn–0.7 wt.%Y Mg alloy containing quasicrystal phase at a temperature of 623 K. After 8 ECAP passes, the grain size of the as-cast alloy is decreased from ∼120 to ∼3.5 μm, and the coarse eutectic quasicrystal phases are broken and dispersed in the alloy. Tensile testing has been performed on the ECAPed Mg–Zn–Y alloy at temperatures of 523 K and 623 K with initial strain rates from 1.5×10−3 to 1.5×10−4 s−1. The ECAPed alloy exhibits a maximum elongation of about 600% when testing at 623 K using an initial strain rate of 1.5×10−4 s−1. Grain boundary sliding is considered to be the dominant deformation mechanism of the Mg–Zn–Y alloy in the temperature and strain-rate range investigated. [Copyright &y& Elsevier]