Development And Research Of High-Strength Cast Rare-Earth Magnesium Alloy

Based on the research progresses of the rare-earth magnesium alloys, several high strength cast magnesium alloys were developed by adding Ag into Mg-Gd-(Y)-Zr alloys.Microstructures and heat treatment processes of the Ag-containing rare earth magnesium alloys were comprehensive studied. The effects of the Ag addition on the microstructures of Mg-Gd-(Y)-Zr alloy were studied using OM、XRD、SEM and EDX. The effects of Ag additions on heat treatment processes and mechanical properties of different alloys were studied.Mg-Gd-(Y)-Ag-Zr alloys exhibit excellent mechanical properties at room temperature. The age-hardening reponse of Mg-Gd-(Y)-Zr alloys can be significantly enhanced by Ag additions, with remarkably increased peak hardness and shortened time to peak. Ag additions can not only enhance the alloy’s strength, but also improve the plasticity of the alloys. After optimum heat-treatment, the UTS and TYS of GWQ832K alloy reach 402MPa and 268MPa repectively at room temperature, with an enlongation of 4.8%.The effects of squeeze casting on the microstructures and mechanical properties of Mg-Gd-Y-(Ag)-Zr alloys were discussed by comparing the different casting processes.