Reinforcement of graphene nanosheets on the microstructure and properties of Sn58Bi lead-free solder

In this study, graphene nanosheets (GNSs) with various percentages (0, 0.01, 0.03, 0.05 and 0.1 wt.%) were successfully incorporated into Sn58Bi lead-free solder. The effects of GNSs on the microstructure, tensile properties, wettability, corrosion resistance, hardness and creep behavior were subsequently investigated. The results show that GNSs refine the microstructure with different features and enhance the wettability efficiently. Tensile and nanoindentation tests reveal that the composite solder with 0.1 wt.% GNSs exhibits about 14% and 38% enhancement in tensile strength and hardness, respectively. With 0.01 wt.% GNSs addition, the elongation is 49% greater than that of the pure Sn58Bi solder alloy. The creep performance and the corrosion resistance are all enhanced by addition of GNSs. The enhancing mechanism of GNSs on the performance of composite solder alloy is also analyzed in this work. (C) 2016 Elsevier Ltd. All rights reserved.