Investigating the influence of rotating magnetic field (RMF) on intermetallic compound crystallization, thermal and mechanical properties in lead-free Sn-Ag-Cu solder alloys during solidification

Abstract

This research delves into the effectiveness of using rotating magnetic field (RMF) during the solidification process of Sn-3.5 wt% Ag-0.7 wt% Cu (SAC 357) alloy. The main goal is to evaluate the effect of RMF on the crystallization of intermetallic compounds (IMCs), as well as to study its implications for the thermal properties and creep resistance of the resulting alloy. It is found that the application of the RMF has a significant promotion effect on the improvement in the grain structure of the primary AgSn phase within the directionally solidified SAC 357 alloy. With the application of RMF, the morphology of the primary AgSn phase transformed from developed dendritic-like to fine needle-like, accompanied by a decrease in grain size, but shows no discernible impact on their composition. This observation is attributed to the influence of Lorentz force and thermo-electromagnetic convection. The implementation of a rotating magnetic field (RMF) resulted in notable enhancements in the thermal properties of the SAC357 solder alloy. Specifically, RMF application led to reductions in both the pasty range and melting temperatures, accompanied by a decrease in undercooling compared to conditions without stirring.The SAC357 alloy, when modified with a magnetic field, demonstrated the longest creep rupture time and higher creep resistance compared to those not subjected to magnetic field modification. This research endeavor aims to address a notable gap in our understanding concerning the behavior of SAC357 solder alloys when subjected to a Rotating Magnetic Field (RMF).