Effects of Al on the failure mechanism of the Sn–Ag–Zn eutectic solder

Tensile testing of Sn–3.7Ag–0.9Zn–xAl (x = 0, 0.5 and 1.0 wt.%) solders have been performed and the failure mechanism was investigated. The results suggest that the addition of Al in the Sn–3.7Ag–0.9Zn solder decreases both the tensile strength and ductility. Moreover, a brittle fracture occurs instead of a ductile fracture with increasing Al content. The fractographs suggest that the fracture mechanism of Sn–Ag–Zn eutectic solder is microvoid coalescence fracture, and the Sn–3.7Ag–0.9Zn–xAl (x = 0.5 and 1.0) solder corresponds to quasi-cleavage crack and cleavage fracture respectively.