Atomic-scale simulations of the local structures of molten Ni1-xCox and Ni1-xFex

In this work, ab initio molecular dynamics simulations have been performed to determine the local structures of molten Ni1-xCox and Ni1-xFex binary alloys. The results reveal that the spin-polarized setting is crucial to simulating Ni1-xFex alloys, while for Ni1-xCox the magnetic and nonmagnetic simulations yield similar results. The bonding tendency of cobalt is not very obvious while Fe atoms prefer hetero-coordination in nickel-based binary alloys. Pentagonal bipyramids are prevalent in both Ni1-xCox and Ni1-xFex, but icosahedral short-range order (ISRO) is not abundant as expected. Besides, the coordination short-range orders of Ni1-xCox and Ni1-xFex are rather similar, distinguishing from those in Ni1-xAlx, which means the local melt structure depends on the specific solute-solvent interaction in nickel-based binary alloys.