Effect of Solution Treatment on Microstructures and Hardness of Mg-Gd-Y-Zr Alloy

Abstract

The influence of the solution treatment (at the temperature of 500-520°C for 4-12 h) on microstructures and mechanical properties of Mg-Gd-Y-Zr alloy was investigated by means of optical microscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) and Vickers hardness measurement. The as-cast alloy contains a microstructure consisting of α-Mg matrix, Mg5Gd phase and Mg24Y5phase. With increasing solution temperature and time, the quantity of the primary particles (Mg5Gd and Mg24Y5) in the alloy continually decreased, and the degree of recrystallization gradually increased, which result in the gradual decrease of the Vickers hardness of the solution-treated alloys.