Influences of rotating magnetic field on microstructure and properties of Sn-Ag-Cu-Sb-Ce solder alloy

The effect of the rotating magnetic field (RMF) on the microstructure and properties of Sn-1.0Ag-0.5Cu-0.5Sb-0.07Ce alloy was investigated. The phase composition of the solder was analyzed by X-ray diffraction (XRD), and the grain size, shape, and phase distribution of the solder were determined by optical microscope (OM), scanning electron microscope (SEM), and energy disperse spectroscopy (EDS). Then, the differential scanning calorimeter (DSC) was employed to evaluate the thermal characteristics of the solder. Finally, the universal mechanical testing machine was used to measure the mechanical properties of the solder at different strain rates. The results showed that the size of beta-Sn was refined and the distribution was more uniform, intermetallic compounds (IMCs) developed from long-strip-like or block shape to finely granular, and the layer spacing decreased after the application of a rotating magnetic field. The pasty range and the melting point of solder decreased slightly (from 5 to 4.7 degrees C) with the RMF. Meanwhile, RMF processing led to an increase (about 13.4%) in the elongation (El.%) of alloy, and the mechanical properties of the solder were enhanced. The research serves as a helpful reference for the development of low-content lead-free solder, which provides a potential solution to the reliability problem of the lead-free joint.