Isochronal Aging Hardening of the Mg-8Gd-3Y-0.5Zr Alloy after Cold Rolling

摘要

By transmission electron microscopy (TEM) and optical microscopy (OM), the isochronal aging hardening law and microstructure have been studied for the Mg-8Gd-3Y-0.5Zr alloy after cold rolling. During isochronal aging process (heated from room temperature to 500°C with the heating rate of 1 °C/min), there are two peak hardness temperature points, which are corresponding to the large number of precipitation of ss' and ss phases, and the peak aging time of the alloy substantially decreased with the increase of deformation reduction. The ss" phases started to precipitate at temperatures of 145°C, 134°C, 127°C and 124°C in the alloy after cold rolling with the reduction of 0%, 8%, 15% and 22%. The heating rate greatly affected the starting precipitation of metastable phases, ss" phases started to precipitate at temperatures of 109°C and 124°C with the reduction of 22% and with the heating rates of 3°C /min and 30°C /min.