Enthalpy of mixing of liquid Cu-Fe-Hf alloys at 1873 K

In the ternary Cu-Fe-Hf system, the mixing enthalpies of liquid alloys were investigated at 1873 K using a high-temperature isoperibolic calorimeter. The experiments were performed along the sections x_Cu/x_Fe = 3/1, 1/1 at x_Hf = 0-0.47 and along the section x_Cu/x_Fe = 1/3 at x_Hf = 0-0.13. The limiting partial enthalpies of mixing of undercooled liquid hafnium in liquid Cu-Fe alloys, Δ_mix anti H_Hf^∞, are (-122 ± 9) kJ mol^-1 (section x_Cu/x_Fe = 3/1), (-106 ± 9) kJ mol^-1 (section x_Cu/x_Fe = 1/1), and (-105 ± 2) kJ mol^-1 (section x_Cu/x_Fe = 1/3). In the investigated composition range, the integral mixing enthalpies are sign-changing. For the integral mixing enthalpy, an analytical expression was obtained by the least squares fit of the experimental results using the Redlich-Kister-Muggianu polynomial.