Advancement solidification microstructure and mechanical properties of Sn–2.0Ag–0.5Cu alloy by applying a rotary magnetic field

Abstract

In the present study, for the first time, rotating magnetic field (RMF) was used to improve the solidification microstructure and mechanical properties of Sn–2.0Ag–0.5Cu (SAC205) solder alloy. Results revealed that the microstructure and tensile behaviour were improved. As observed, after applying RMF, grain size of β-Sn reduced to be ~ 10 μm which was decreased by ~ 60%. As well, an average size of IMCs formed in SAC205-B alloy were ~ 10–30 μm which were reduced by ~ 40–66%. Therefore, the growth rate of IMCs has been successfully suppressed with RMF. Interestingly, a decrease in grain size and IMCs thickness indicated the beneficial effect of applying RMF on the solder alloy. Consequently, in terms of tensile tests, SAC205 with RMF showed the highest strength over the entire temperatures and strain rates range. Moreover, UTS, YS, YM and El. % at room temperature (25 °C) of SAC205 alloy with RMF were ~ 9.0%, ~ 26.0%, ~ 8.0% and ~ 9.0% greater than that of RMF-free SAC205 alloy. Also, results showed that tensile strength of SAC205 alloy with and without RMF are remarkably sensitive to changes in both temperature and strain rate. Furthermore, the average stress exponent (n) and activation energy (Q) for RMF-free SAC205 and SAC205 with RMF solder alloys have been discussed. The obtained results should prove beneficial in the microelectronic packaging industry.