Multiscale study of the influence of chemical order on the properties of liquid Li-Bi alloys

Abstract

The static structure and diffusion properties of Li-Bi liquid alloys at three compositions are investigated by molecular dynamics simulations. Due to the strong chemical order shown by these alloys, a multiscale approach is applied, fitting empirical pair potentials to data from ab initio molecular dynamics simulations to subsequently perform large-scale classical simulations. In this way, the partial structure factors as well as the self-diffusion and interdiffusion coefficients can be computed with sufficient accuracy to be discussed quantitatively. This approach is validated by comparing our predictions with experimental structure factor measurements. A marked heterocoordination is observed, which strongly influences the diffusion properties. These observations are consistent with an evolution toward ionic bonding at the Li${}_{75}$-Bi${}_{25}$ composition.