Role of erbium in microstructure and mechanical properties of Sn58Bi42 solder alloy

Abstract Erbium (Er) with a few weight percent (0, 0.1, 0.3 and 0.5 wt%) were synthesized into composite Sn58Bi42 alloys in this work. The effects of the addition of Er element on the microstructure and the mechanical properties of the Sn58Bi42 alloy were surveyed. Er added Sn58Bi42 alloys refined the microstructure significantly compared to the Sn58Bi42 alloy. Based on the microstructure refinement, the creep depth decreased by 21% as the capacity of Er is 0.5 wt%. This work also evaluates other mechanical properties containing hardness and elastic modulus, which correlated to the microstructure improvement of the composite solder alloy. Moreover, nanoindentation testing results show that the creep mechanism of Er micro-alloying Sn58Bi42 is core diffusion to control grain boundary sliding.