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℃ with the heating rate of l℃/min), there are two peak hardness temperature points, which are corresponding to the large number of precipitation of β' and β phases, and the peak aging time of the alloy substantially decreased with the increase of deformation reduction. The β" phases started to precipitate at temperatures of 145℃, 134℃, 127℃ and 124℃ 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. P" phases started to precipitate at temperatures of 109℃ and 124℃ with the reduction of 22% and with the heating rates of 3℃ /min and 30℃ /min.