Multiscale study of the influence of chemical order on the properties of liquid Li-Bi alloys
Résumé
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 selfdiffusion 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 Li75-Bi25 composition.