Experimental Investigation and Thermodynamic Description of the Cu–Ti–V System

The phase equilibria of the Cu–Ti–V system were investigated via key experiments coupled with thermodynamic modeling. The isothermal sections at 600 °C, 700 °C, and 800 °C were constructed using X-ray diffraction (XRD) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDS). The solubilities of Cu in the (βTi, V) phase and V in intermediate phases Cu₄Ti, Cu₃Ti₂, Cu₄Ti₃, CuTi, CuTi₂, and CuTi₃ were determined. Based on the thermodynamic descriptions of three binary subsystems and the experimental data, the thermodynamic assessment of the Cu–Ti–V system was carried out by means of the CALPHAD (CALculation of PHAse Diagrams) method. A set of thermodynamic parameters for the Cu–Ti–V system was obtained and the calculated phase equilibria were consistent with the experimental results. The liquidus projection and the reaction scheme of the Cu–Ti–V system were constructed. This work provides important phase equilibria and thermodynamic data for the composition and process design of new copper alloys.