HIGH TEMPERATURE DEFORMATION FLOW OF A ZK60A MAGNESIUM ALLOY AFTER EXTRUSION

Abstract

Flow behavior of a ZK60A magnesium alloy after continuous casting and subsequent extrusion was examined in tension at a range of strain rates of 3.0x10(-6) - 1.0x10(-2) s(-1) at temperatures of 473-623K. The results demonstrated that the alloy exhibited a maximum elongation of similar to 250% at 523K when tested at an initial strain rate of 1.0x10(-5) s(-1) and strain rate sensitivity, m, of similar to 0.3-0.4 and the activation energy of similar to 94 kJ/mol were calculated under the testing conditions. The detailed investigation suggested that the high temperature flow of the ZK60A alloy having submicrometer grains demonstrates quasi-superplastic flow behavior controlled by a dislocation viscous glide process.