Experimental Investigation and Thermodynamic Calculation of the Phase Equilibria in the Cu-Nb-Zr Ternary System

The phase equilibria of the Cu-Nb-Zr ternary system at 900, 1000 and 1100 °C were experimentally investigated by optical microscopy and electron probe microanalysis on the equilibrated alloys. Combined with the obtained experimental results, the phase equilibria of Cu-Nb-Zr ternary system were thermodynamically optimized using the CALPHAD (calculation of phase diagrams) method. The Gibbs free energies of the phases in the present work were described by appropriate models. A consistent set of the thermodynamic parameters leading to reasonable agreement between the calculated data and experimental results was obtained in the Cu-Nb-Zr ternary system.