Effects of Zn addition and aging treatment on tensile properties of Sn–Ag–Cu alloys

Abstract The effects of adding small amounts of Zn and conducting an aging treatment at elevated temperatures on the microstructure and tensile properties of low-Ag Sn–Ag–Cu alloys were investigated. The addition of Zn to Sn–Ag–Cu alloys inhibited the growth of intermetallic compounds. As the amount of Zn increased, the flow stress increased both before and after the aging treatment. In particular, the Sn–1Ag–0.3Cu–1Zn alloy exhibited the highest flow stress among all the examined alloys. Although the flow stress of the Sn–3Ag–0.5Cu alloy was originally higher than that of the Sn–1Ag–0.1Cu–0.4Zn and Sn–1Ag–0.3Cu–0.7Zn alloys, the flow stress of these two alloys was higher after aging for 500 h at 398 K than that of the Sn–3Ag–0.5Cu alloy. The addition of small amounts of Zn in Sn–Ag–Cu alloys suppressed the decline in the flow stress after the aging treatment.