Phase equilibria of the Cu–Zr–Si system at 750 and 900 °C

Phase equilibria in the ternary Cu–Zr–Si system at 750 and 900 °C have been experimentally investigated via electron probe micro-analyzer (EPMA) and X-ray diffraction (XRD) analysis on the equilibrated alloys. The results show the presence of eight three-phase regions at 750 °C and seven three-phase regions at 900 °C. Four ternary phase: τ₁ (Zr₃Cu₄Si₆, tI26-Zr₃Cu₄Si₆), τ₄ (Zr₃Cu₄Si₄, oI22-Gd₃Cu₄Ge₄), τ₅ (ZrCuSi, oP12-Co₂Si), and τ₆ (Zr₃Cu₄Si₂, 2hP9-Fe₂P) were confirmed to exist in the Cu–Zr–Si ternary system at 750 and 900 °C. At 900 °C, the dark gray phase, the chemical composition of which is close to η-Cu₃Si, is confirmed to be the liquid phase. Moreover, the solubilities of Cu in ZrSi₂, SiZr and Zr₃Si₂ are considerably small. The solubility of Zr in η-Cu₃Si is determined to be negligible. The newly determined phase equilibria of the Cu–Zr–Si system in this work can provide important experimental data for the thermodynamic assessment of the Cu–Zr–Si system and to develop the Cu–Zr–Si alloys and related transition metal silicides.