Enthalpy of Mixing of Liquid Cu-Fe-Zr Alloys at 1873 K (1600 A°C)

The enthalpies of mixing of liquid Cu-Fe-Zr alloys were determined at 1873 K (1600 A degrees C) by using a high-temperature isoperibolic calorimeter. The measurements were performed along sections x (Cu)/x (Fe) = 3/1, 1/1, 1/3 in the composition range x (Zr) = 0 to 0.55. The limiting partial enthalpies of mixing of undercooled liquid zirconium in liquid Cu-Fe alloys are (-91.8 +/- A 8.4) kJ mol(-1) (section x (Cu)/x (Fe) = 3/1), (-94.1 +/- A 12.8) kJ mol(-1) (section x (Cu)/x (Fe) = 1/1), and (-107.3 +/- A 15.6) kJ mol(-1) (section x (Cu)/x (Fe) = 1/3). The integral mixing enthalpies are sign changing over the investigated composition range. The Redlich-Kister-Muggianu polynomial was used for the least square fit of the experimental results in order to obtain an analytical expression for the integral mixing enthalpy.