Hot workfability behavior of as-cast Mg-Zn-Y-Zr alloy

Hot workability of conventional magnesium alloys, such as AZ61, AZ80 and ZK60, have been proposed or reported in previous literature. However, no detailed investigation has been conducted regarding the hot workability of as-cast Mg-Zn-Y-Zr alloy. The hot deformation characteristics of as-cast Mg-Zn-Y-Zr alloy were investigated using constitutive equations and processing maps at temperatures between 200 and 400 degrees C and strain rates ranging from 0.001 to 1 s(-1). Backward extrusion of the component with multi-hole was carried out to evaluate the workability of Mg-Zn-Y-Zr alloy at elevated temperatures. The results show that the flow stress has been found to be strongly dependent on temperature as well as strain rate. By means of regression analysis for the Arrhenius type equation of flow behavior, the apparent average activation energy of deformation was determined as 251.228 KJ/mol, and the stress exponent was 6.231. The processing map technique was utilized to determine the practical processing parameters. The reasonable process parameters of as-cast Mg-Zn-Y-Zr alloy were deformation temperatures of 350-400 degrees C and stain rates of 0.001-0.1 s(-1). The reproduction of Mg-Zn-Y-Zr alloy components with multi-hole was shown to be good, and no problem was experienced in filling during backward extrusion using reasonable process parameters. (C) 2013 Elsevier B.V. All rights reserved.