Thermodynamic properties of Fe-Ni solid solutions studied by Fe Mössbauer spectroscopy

The room temperature Mössbauer spectra of ⁵⁷Fe were measured for Ni_1−xFe_x solid solutions with x in the range 0.01≤x≤0.10. The obtained data were analysed in terms of short range order parameter (SRO) and the binding energy E_b between two iron atoms in the studied materials using the extended Hrynkiewicz-Królas idea. It was found that the binding energy is positive or Fe atoms interact repulsively. The extrapolated value of E_b for x=0 was used for computation of enthalpy of solution of Fe in Ni. Finally the values of enthalpies of solution were used to predict the mixing enthalpy curve for the Fe-Ni solid solutions. The results were compared with corresponding value given in the literature, which was calculated theoretically using DFT techniques, as well as with the value obtained from experimental calorimetric data and resulting from the cellular atomic model of alloys by Miedema.