Solidified microstructure and phase equilibria of the Cu–Cr–X (X=Mg, Y) ternary systems

Abstract

The Cu–Cr alloys with magnesium and yttrium exhibit appealing high-strength and high-conductivity (HSHC) characteristics. Anticipated contributions to the design of HSHC copper alloys include new insights from understanding the phase equilibria, solidified microstructure, and thermodynamics of the Cu–Cr–X (X = Mg, Y) systems. Five Cu–Cr–Y alloys and three Cu–Cr–Mg alloys were melted through arc melting and powder metallurgy, respectively. An analysis was conducted on the primary phases and solidification path of the as-cast Cu–Cr–Y alloys. Five three-phase regions in the Cu–Cr–Y system and three in the Cu–Cr–Mg system at the isothermal sections of 673 K were identified using XRD and EPMA. No ternary compound was discovered among either of these systems. The agreement between the experimental data and the calculated isothermal sections and liquidus projection derived from the thermodynamic description of the binary systems is quite good. The investigation on phase equilibria in Cu–Cr–X (X = Mg, Y) systems in this study helps in developing the thermodynamic database for multi-component copper alloys.

Keywords

• Cu–Cr–Y
• Cu–Cr–Mg
• Phase equilibria
• Solidified microstructure
• Liquidus projection
• CALPHAD