Effect of Aging Treatment on Tensile Behaviors of Cast Mg-9Gd-4Y-0.5Zr Alloy

Aging treatment is a significant method for improving the tensile properties of cast Mg-Gd-Y alloy. In this article, tension tests were conducted on the Mg-9Gd-4Y-0.5Zr (wt.%) alloy after various artificial aging treatments to examine the influence of aging treatment on mechanical behaviors, especially the work-hardening behavior, which is critical for both strength and ductility. It is interesting that for the three types of samples peak-aged and over-aged at 200°C and peak-aged at 225°C, the variation of yield strength was small, whereas the ductility increased from 0.68% and 1.31% of the former two to 2.24% of the last one. It was considered that precipitate spacing might be the dominant influence factor for the ductility by influencing the dynamic recovery in stage III of work hardening. Moreover, the origin of the high work-hardening rate, responsible for the high strength of aged alloys, was also discussed.