Experimental measurement on the phase equilibria of the Mg–Ag–Cu ternary system at 350 and 400 °C

The phase equilibria of the Mg–Ag–Cu ternary system at 350 and 400 °C were experimentally investigated using twenty-eight key samples. The phase equilibria and compositions in key samples were investigated using scanning electron microscopy (SEM) equipped with energy-dispersive spectroscopy (EDS). Powder X-ray diffraction (XRD) technique was used to analyze the crystal structure and solid solubility of compounds. Five three-phase equilibria and several two-phase equilibria have been determined at 350 and 400 °C. The solid solubility range of Cu in the compounds Mg3Ag, MgAg and fcc(Ag) were examined at 350 and 400 °C. The maximum solid solubility of Ag in the compound MgCu2 was found to be 11.46 at.% and 11.25 at.% with a constant value of about 66 at.% Cu at 350 and 400 °C, respectively. Besides, the solid solubility limits of Ag in the compounds Mg2Cu and fcc(Cu) were found to be less than 5 at.% at 350 and 400 °C. No ternary compound was observed in the present work.