Isothermal sections of the Mg-rich corner in the Mg–Sn–Y ternary system at 300 and 400 °C

The phase equilibria of the Mg-rich corner in the Mg–Sn–Y ternary system at 300 and 400 °C have been determined through equilibrated alloy method by means of X-ray diffraction (XRD), scanning electron microscopy with assistance of energy dispersive spectroscopy of X-ray (SEM–EDS), and thus the isothermal sections of this ternary system have been constructed. The equilibrium phase relations have no change with increase from 300 to 400 °C, and there are both four intermetallic compounds in equilibrium with the α-Mg solid solution at the two temperatures, i.e. Mg2Sn, MgSnY, Sn3Y5 and Mg24+xY5. It is interesting to find that either Y or Sn can be soluble in the α-Mg solid solution but they are not simultaneously soluble. The solubility of Mg in the compound Sn3Y5 increases with the temperature from 300 to 400 °C. According to the phase relations and high-melting-point characteristics of these intermetallics in this ternary system, such as Sn3Y5 phase, etc., it is expected that the Mg–Sn–Y-based alloy could be a promising creep resistant alloy by appropriate alloy design and processing.