Novel SiC nanoparticles-containing Sn–1.0Ag–0.5Cu solder with good drop impact performance

In this study, the SiC nanoparticles were successfully fabricated by high energy ball milling. Mechanical mixing technique has been used to disperse nanometric SiC in Sn–1.0Ag–0.5Cu (SAC105) solder at 450 °C for 2 h. In comparison with SAC(105) solder, the addition of SiC nanoparticles can effectively increase the primary β-Sn phase and decrease the percentage of Ag3Sn and Cu6Sn5 IMC particles, which produce a weak interface with the β-Sn matrix. The formation of few numbers of IMC particles, together with the weak interface have resulted in slight decrease of ultimate tensile strength (UTS), 0.2% yield strength (0.2%YS) and elastic modulus, whereas the ductility has improved. The improved plasticity is due to the structural refinement of the sub-grain sizes of primary β-Sn phases, which makes the composite solder to display large elongation. The addition of SiC nano-sized particles can also effectively reduce the undercooling and pasty range, while the melting temperature is maintained at the SAC105 level, indicating that the novel composite solder is fit for existing soldering process. These effects could increase the elastic compliance and plastic energy dissipation ability of the bulk solder, which play an important role in drop impact performance enhancement.