Effect of adding 0.5Â wt% ZnO nanoparticles, temperature and strain rate on tensile properties of Sn-5.0Â wt% Sb-0.5Â wt% Cu (SSC505) lead free solder alloy

This study investigates the effect of adding 0.5 wt% ZnO nanoparticles into Sn-5 wt% Sb-0.5 wt% Cu (SSC505) solder alloy on the growth of intermetallic compounds (IMCs) as well as the associated changes of microstructure. It was found that, the morphologies of the IMCs transformed to refinement forms due to the adsorption effect of ZnO nanoparticles. Systematic study of tensile properties was performed for bulk solders over a wide range of strain rates at various temperatures to determine the plastic deformation mechanism. Obviously, the ultimate tensile strength (UTS) and the yield stress (σy) were improved. This can be attributed to reinforcement of ZnO nanoparticles, refined β-Sn grains and IMCs that could obstruct the dislocation slipping. The obtained results are consistent with the prediction of the classic theory of dispersion strengthening. Furthermore, the average activation energy (Q) for plain and composite solders were 57 and 59 kJ/mol, respectively, which close to that of pipe-diffusion mechanism in Sn based solder matrix.