N-body potential for simulation of α and β phases of zirconium

We present a new interatomic potential for atomistic modeling of a- and fl-phases of zirconium. The potential was developed within the framework of the N -body approach, which takes into account pair, three-body and many-body interactions. The new potential predicts a wide range of zirconium properties in agreement with known experimental and DFT data including structural energies, elastic constants, energies of point and planar defects, thermodynamic properties, such as melting temperature and a - fl transition temperature. The potential predicts the mechanical instability of the fl-phase of zirconium at 0 K, as well as relaxation effects of internal degrees of freedom in elastic constants. The predicted interstitial stacking fault energy is in a good agreement with the DFT data. The formation energies of self-interstitial atoms in the a-phase are in agreement with the known DFT values, predicting the basal octahedral (BO) configuration as the most stable. The potential predicts a spontaneous fl - a transition with decreasing temperature. The calculated a - fl phase transition temperature is 20% higher than the experimental value. The potential accurately predicts the melting temperature of zirconium, due to which a good agreement with the experimental data was obtained on the temperature dependencies of the diffusion coefficients for the a- and fl-phases of zirconium. For both phases, the main contribution to the diffusivity is due to vacancies, while the corresponding values for interstitials are by one or two orders of magnitude lower. The potential predicts the deviation from the Arrhenius law of the temperature dependence of the diffusion coefficient for the fl-phase of zirconium, due to the nonlinear dependence of the Gibbs energy of a vacancy formation on temperature. The constructed potential can be used for molecular dynamics simulations of a- and fl-phases of zirconium and further development of interatomic potentials within the framework of the N -body approach for alloys containing zirconium.