Simulation on in-situ crystal growth of lead-free solder Sn-57Bi alloy

Abstract

Lead-free solder Sn-57Bi alloy is a good candidate material for electronic packaging. However, it is difficult to observe in-situ crystal growth process of Sn-57Bi alloy at high temperature and pressure environment. In this paper, based on the Monte Carlo method with the effect of volumetric and interfacial free energy taken into consideration quantitatively, a probability model for eutectic growth is established to simulate the in-situ crystal growth of Sn-57Bi alloy. The in-situ crystal growth of Sn-57Bi alloy at different undercoolings is studied. The simulation result shows the coupled growth of two phases in eutectic alloys, along with that lamellar spacing decreases and growth velocity increases with the increase of undercooling, agreeing with the reported experimental works on the eutectic growth. This work presents a good method to study the in-situ crystal growth process of alloys.