Effects of Ni addition on mechanical properties of Sn58Bi solder alloy during solid-state aging

In this study, Ni functionalized Sn58Bi solder alloys were successfully synthesized. Composite solders up to 1 wt% Ni reinforcement were prepared. Microstructures and mechanical properties of composite solders after sintering and solid-state aging for 120 h and 240 h were compared with those of the pure Sn58Bi solder. The results indicate that the elastic modulus, tensile and yield strength increase with the increasing Ni content during the solid-state aging, which is because Ni can decrease the CTE and refine the microstructure of SnBi solder. The ductility of composite solders presents a non monotonic trend with the increasing Ni content and aging time because the concentrated Ni3Sn4 grains form at the solder matrix. The hardness can reflect the tensile and yield strength transformation veritably. Besides, the hardness varies with tensile and yield strength following the linear relationships.