Effects of Zn/Gd ratio and content of Zn, Gd on phase constitutions of Mg alloys

The phase constitutions of Mg-Zn-Gd alloys in the Mg-rich corner were investigated using XRD, SEM and TEM. The effect of Zn/Gd ratio and content of Zn, Gd element on the phase constitutions of Mg-Zn-Gd alloys were studied. Formation range of I-phase in the Mg-Zn-Gd system in the Mg-rich corner has been confirmed using conventional cast process. I-phase could been formed for alloys in the range of Zn/Gd ratio from 1.5 to 40, or with Zn above 3 at.% under the condition of Zn/Gd ratio of 10 and 25.