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The microstructure evolution and mechanical properties of Mg-15Gd-3Y alloy were investigated in the as-cast and heat treated conditions.The microstructure evolution from as-cast to cast-T4 states involved α-Mg solid solution+Mg5(Gd,Y) phase→α-Mg supersatu-rated solid solution+rare earths compound Mg3(Gd1.26,Y0.74)→α-Mg supersaturated solid solution+rare earths compound Mg3(Gd0.745,Y1.255).It showed that 480 oC/4 h was the optimal solution treatment parameter.If the solution temperature was high or the holding time was long,such as 520 oC/16 h,an overheating phenomenon would be induced,which had a detrimental effect on the mechanical properties.When age-ing at 225 and 200 oC,the alloy would exhibit a significant age-hardening response and great long-time-age-hardening potential,respectively.The best mechanical properties were obtained at the parameters of 480 oC/4 h+225 oC/16 h,with the UTS of 257.0 MPa and elongation of 3.8%.
The microstructure evolution and mechanical properties of Mg-15Gd-3Y alloys were investigated in the as-cast and heat treated conditions. The microstructure evolution from as-cast to cast-T4 states involving α-Mg solid solution + Mg5 (Gd, Y) phase → α-Mg supersatu-rated solid solution + rare earths compound Mg3 (Gd1.26, Y0.74) → α-Mg supersaturated solid solution + rare earths compound Mg3 (Gd0.745, Y1.255) .It showed that 480 oC / 4 h was the optimal solution treatment parameter. If the solution temperature was high or the holding time was long, such as 520 oC / 16 h, an overheating phenomenon would be induced, which had a detrimental effect on the mechanical properties. age-ing at 225 and 200 oC, the alloy would exhibit a significant age-hardening response and great long-time-age-hardening potential, respectively. The best mechanical properties were obtained at the parameters of 480 oC / 4 h + 225 oC / 16 h, with the UTS of 257.0 MPa and elongation of 3.8%.