Compositional effects in the liquid Fe–Ni–C system at high pressure

Abstract We performed molecular dynamics simulations based on density functional theory to systematically investigate the Fe–Ni–C system including (1) pure Fe and Ni; (2) binary Fe–Ni, Fe–C, Ni–C; (3) ternary liquid compositions at 3000 K three simulation volumes corresponding pressure ( P ) up 83 GPa. Liquid structural properties, coordination numbers, are analyzed using partial radial distribution functions. Self-diffusion coefficients determined atomic trajectories asymptotic slope of time-dependent mean-square displacement. The results indicate that average interatomic distance between two atoms r Fe–Fe decreases with is sensitive Ni X C concentration, although effects opposite: increasing , but increases . Average Fe–C Ni–C values also decrease generally remain constant lowest points, a change carbon from ~ 6.8 8.0, then additional once complete. Carbon clustering occurs in both (especially Ni–C) short-range C-C (~ 1.29 1.57 Å), typical for diamond graphite. self-diffusion consistent high- diffusion data extrapolated experiments conducted lower temperature T ). A subset was 1675 2350 estimate effect diffusion, yielding an activation enthalpy 53 kJ/mol volume 0.5 cm 3 /mol.