Experimental investigation and thermodynamic calculation of the Cu-Cr-Ti ternary system

The phase equilibria of the Cu-Cr-Ti ternary system were investigated based on key experiments coupled with thermodynamic modeling. Eighteen ternary alloys were prepared to determine the isothermal sections of the Cu-Cr-Ti system at 600 and 800 degrees C by means of X-ray diffraction (XRD) and scanning electron microscopy equipped with energy dispersive X-ray spectroscopy (SEM/EDS). Seven three-phase regions have been determined. A ternary compound & tau;1 was confirmed. The solubilities of Cr in the Cu-Ti binary compounds and Cu in the Cr-Ti binary compounds were measured. The substitutional and sublattice models were used to describe the solution phases and intermediate phases, respectively. Based on the thermodynamic descriptions of three binary systems as well as the experimental phase equilibria data available from the literature and the present work, thermodynamic assessment of the Cu-Cr-Ti system was carried out using the CALPHAD (CALculation of PHAse Diagrams) approach. A set of thermodynamic parameters was obtained and the isothermal sections and the liquidus projection of the Cu-Cr-Ti system were calculated. The calculated results agree well with the experimental data.