Novel low Ag-content Sn-Ag-Cu-Sb-Al solder alloys with enhanced elastic compliance and plastic energy dissipation ability by applying rotating magnetic field

摘要

The main scope of this research is to investigate the impact of rotating magnetic field (RMF) on the physical properties of the Sn-0.5Ag-0.5Cu-2.0Sb-0.1Al (SAC0505SbAl) solder alloy. The application of RMF during molten alloy cooling showed prominent effect on the morphology, thermal properties, and the consequent mechanical characteristics. It was shown that the dendritic morphology was changed from columnar dendrites to equiaxed grains with the application of RMF. In addition, RMF processing modified the eutectic phases in the alloy matrix. These notable modifications have resulted in a substantial increase in ductility (～30%) with a slight decrease in tensile parameters (UTS and YS). Such effects could enhance elastic compliance and plastic energy dissipation ability of solder alloys, which plays superbly fundamental function in drop-impact reliability. Differential scanning calorimetry (DSC) analysis reveals that significant decrease in pasty range (from 10.8 to 7.5 °C) and undercooling (from 13.1 to 9.0 °C) was attained after applying RMF. The stress exponent (n), the activation energy (Q), and deformation mechanism of the SAC0505SbAl alloy processed with and without RMF were discussed in detail. The obtained results are certainly expected to fill the knowledge gap about the behavior of these recently developed solder alloys under the effect of RMF that are potential alternatives as Pb-free interconnecting material in microelectronic packaging industry.