The phase equilibria of the Cu-Cr-Ni and Cu-Cr-Ag systems: Experimental investigation and thermodynamic modeling

The phase equilibria of the Cu-Cr-Ni and Cu-Cr-Ag systems were investigated by a combination of key experiments and thermodynamic modeling. Eleven and fourteen ternary alloys were prepared to determine the isothermal sections of the Cu-Cr-Ni system at 800 and 1000 degrees C, and the Cu-Cr-Ag system at 500, 600, 650 and 700 degrees C, respectively, by means of X-ray diffraction (XRD) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX). The three- and two-phase regions were determined. The solubility of the third elements in the phases of the binary systems was measured. No ternary compound was found in these two ternary systems. Based on the experimental equilibria data from the literature and the present work, a thermodynamic modeling of the Cu-Cr-Ni and Cu-Cr-Ag systems was performed by the CALPHAD (CALculation of PHAse Diagrams) method. The substitutional solution model was used to describe the solution phases. A set of self-consistent thermodynamic parameters of the Cu-Cr-Ni and Cu-Cr-Ag systems was obtained. Most of the reliable experimental data can be well reproduced by the present thermodynamic modeling.