Atomistic modelling of the immiscible Fe–Bi system from a constructed bond order potential

Abstract

An analytical bond-order potential (BOP) of Fe–Bi has been constructed and has been validated to have a better performance than the Fe–Bi potentials already published in the literature. Molecular dynamics simulations based on this BOP has been then conducted to investigate the ground-state properties of Bi, structural stability of the Fe–Bi binary system, and the effect of Bi on mechanical properties of BCC Fe. It is found that the present BOP could accurately predict the ground-state A7 structure of Bi and its structural parameters, and that a uniform amorphous structure of Fe100−x Bi x could be formed when Bi is located in the composition range of 26 ⩽ x < 70. In addition, simulations also reveal that the addition of a very small percentage of Bi would cause a considerable decrease of tensile strength and critical strain of BCC Fe upon uniaxial tensile loading. The obtained results are in nice agreement with similar experimental observations in the literature.