Enthalpies of Mixing in Al−Ce−Co Liquid Alloys

The enthalpies of mixing in liquid alloys of the ternary Al−Ce−Co system were determined along four sections (with a constant mole fraction ratio x Ce / x Co =0.77/0.23 and x Ce / x Co =0.35/0.65 up to x Al =0.2 at 1700 K; with x Al / x Co =0.76/0.24 up to x Ce =0.3 and x Al / x Ce =0.30/0.70 up to x Co =0.23 at 1823 K) via isoperibolic calorimetry. The enthalpies of mixing in the liquid Al−Ce−Co alloys are large exothermic values. A comparison of the experimentally obtained results for the enthalpies of mixing of liquid alloys and those calculated by the regular Redlich‐Kister‐Muggianu model, taking into account only the data for binary constituent systems, indicates the specific exothermic ‘ternary’ contribution to the energy of formation of Al−Ce−Co ternary alloys. Data on the partial enthalpy of mixing of cobalt at infinite dilution indicate the involvement of cerium 4 f‐electron in the process of alloy formation.