Effects of coupled stressing and solid-state aging on the mechanical properties of graphene nanosheets reinforced Sn-58Bi-0.7Zn solder joint

With the addition of 0.075 wt% graphene nanosheets (GNSs), the mechanical properties of coupled and aged solder joint were respectively investigated in this study. During the tensile tests, the weakening of the anode interface between intermetallic compounds (IMCs) and Bi layer significantly affected the ultimate tensile strength (UTS) of electromigration (EM) and thermal aging coupled solder joint. The formation of vacancies and stress concentration at the Cu-Sn-Zn/Cu-Zn interface in the aged solder joint was ascribed to the Bi segregation and GNSs. Nanoindentation results showed that the creep resistance of coupled solder joint was higher than that of the aged solder joint, which was because that the Bi layer, GNSs and cracks played a role of load transfer at the solder joint interface in coupled sample.