Inherited effects from artificial aging on the tensile creep behaviors of hot-rolled Mg–7.5wt%Y alloy

Herein, the impacts of inherited attributes from artificial aging treatment of the hot-rolled Mg–7.5wt%Y alloy’s tensile creep resistance were investigated at 220~280 °C. The hot-rolled alloy was divided into two groups; one group was solution-treated and then labeled as the AS sample, while the other group was then followed by peak-aging and labeled as the AA sample. Cross-slip controlled the creep behavior of the AS sample, while the creep behavior of the AA sample was controlled by cross-slip combined with the pyramidal slip. During tensile creep, cross-slip induced the dynamic precipitation of facet-like β ′ phases in the AS sample and resulted in early crack initiation next to grain boundaries. On the contrary, the platelike β and facet-like β ′ phases inherited from artificial aging effectively postponed the dynamic precipitation in the AA sample and led to a relatively uniform stress distribution. Besides, the constituents in pyramidal slip arranging as dislocation networks further promoted the creep resistance in the AA sample. As a result, aging treatment could promote the creep resistance of Mg–7.5wt%Y alloy significantly.