Melting process of lead-bismuth eutectic alloy from atomistic simulation

Abstract

First principles calculation shows that hexagonal-close-packed (HCP) is the ground-state structure of solid Pb45Bi55 with the lowest heat of formation among the four studied structures. Ab initio molecular dynamics simulation is then conducted to identify the structural change of the melting process of Pb45Bi55 from HCP to liquid. It is revealed that during the melting process, the second and third peaks of pair correlation function of the solid state disappear, and instead a new peak appears in the liquid state, while the position of the first peak remains unchanged. Simulation also shows that during the solid-to-liquid phase transition, the total energy and coordination number experience an abrupt decrease and increase with the increase of temperature, respectively. Interestingly, Pb and Bi atoms are apt to mix with each other in both solid and liquid states. The derived results are in nice agreement with experimental and calculated data in the literature, and could provide a deep understanding of the melting process of the Pb–Bi eutectic alloy.