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

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 Fe_100-Bicould 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.