Experimental Study of Phase Relations in the Mg-Er-Si System Focused on Mg-Rich Region at 300 and 400 °C

The phase equilibria and compositions in the magnesium (Mg) rich part of the Mg-Er-Si ternary system at 300 and 400 °C were systemically investigated through the equilibrated alloy method by using x-ray diffraction and scanning electron microscopy assisted with energy dispersive spectroscopy of x-ray. The results show that in the composition range of our study the equilibrium of Er2MgSi2 with the (Mg) solid solution, Er5Mg24, and Mg2Si exists at both temperatures. A certain amount of Mg atoms can be replaced by Er and Si element, but they cannot replace Mg atom simultaneously. The homogeneity ranges of Mg solid solution as well as the solid solubilities of the intermediate phases at different temperatures are reported.