Molecular dynamics simulation of thermophysical properties of undercooled liquidcobalt

Abstract

Molecular dynamics simulations with two different embedded-atom-method (EAM)potentials are applied to calculate the density, specific heat and self-diffusioncoefficient of liquid cobalt at temperatures above and below the melting temperature.Simulation shows that Pasianot’s EAM model of cobalt constructed on the basis ofa hcp structure is more successful than Stoop’s EAM model in the frameworkof a fcc structure in predicting the thermophysical properties of liquid cobalt.Simulations with Pasianot’s EAM model indicate that the density fits intoρ = 7.49–9.17 × 10−4(T−Tm) g cm−3, and the self-diffusioncoefficient is given by D = 1.291 × 10−7exp(−48 795.71/RT) m2 s−1. Dissimilar to the linear dependence of the density and the Arrhenius dependence of theself-diffusion coefficient on temperature, the specific heat shows almost a constant value of38.595 ± 0.084 J mol−1 K−1 within the temperature range of simulation. The simulated properties of liquid cobalt arecompared with experimental data available. Comparisons show reasonable agreementsbetween the simulated results from Pasianot’s EAM model and experimental data.