Mixing Enthalpy Measurements of Liquid Fe-Ti Alloys by Levitation Alloying Calorimetry and Calculation of the Thermodynamic Properties of Mixing.

Abstract

Mixing enthalpies, ΔHm, of liquid iron-titanium alloys were measured in dependence of the composition by levitation alloying calorimetry. The measurements were carried out at T=1950 K up to xTi=0.42 in the iron rich concentration range and at T=2112 K up to xFe=0.31 in the titanium rich concentration range. The mixing enthalpy was found to be exothermic. The temperature dependence of ΔHm could be described with help of the regular associate model. On the basis of an adapted function for the mixing enthalpy calculations of the excess heat capacity, the free energy of mixing, the partial free energies of mixing and the activities of iron and titanium are performed. The comparison of the calculated activities with corresponding experimental data from the literature shows a good accordance.