Interatomic Potential Development for the Fe–Ni System and Evaluation of the Elastic Properties of an Iron–Nickel Alloy

We have developed Morse-type pair interatomic potentials for γ-Fe and Ni and an asymmetric pair interaction potential for Fe and Ni atoms using Grüneisen parameters and sublimation energies calibrated for the first time with the use of empirical temperature dependences of the shear modulus. The pair potentials obtained in classic Morse form have been used for the first time to derive temperature dependences of bulk modulus in a wide temperature range, from 600 to 1000°C, with the possibility of extrapolation to 1100°C, which are in satisfactory agreement with appropriate experimental data for iron, nickel, and an iron–nickel alloy with an FCC structure. The interatomic potentials obtained in this study can be used to analyze activation energies for diffusion processes, vacancy nucleation, and other effects in alloys of the iron–nickel system.