Mixing enthalpy measurements of liquid Ti-Zr, Fe-Ti-Zr and Fe-Ni-Zr alloys

The mixing enthalpies of liquid Ti-Zr, Fe-Ti-Zr and Fe-Ni-Zr alloys were me asured by levitation alloying calorimetry. The mixing enthalpy of Ti-Zr all oys is slightly exothermic and symmetric with an extreme value of -5.2 kJ m ol(-1). It can be described according to the regular solution model. Experi mental investigations of the mixing enthalpies of the strongly non-ideal bi nary systems Fe-Ti, Fe-Zr and Ni-Zr had already been subject of earlier wor ks. Based on experimental data temperature dependent descriptions of the mi xing enthalpies were calculated with a regular associate model. From the mo del parameters of the binary subsystems the mixing enthalpy of the respecti ve ternary system can be predicted. Model calculations of the mixing enthal pies of liquid Fe-Ti-Zr and Fe-Ni-Zr alloys were performed along different concentration sections and compared with experimental data, respectively. A good accordance was observed. The mixing enthalpies of liquid Fe-Ti-Zr and Fe-Ni-Zr alloys are given at T = 2152 K and T = 1892 K in form of isoentha lpy diagrams, respectively. Moreover, with help of the temperature dependen ce of the mixing enthalpy the excess heat capacities of the alloys were cal culated.