Microstructure refinement, characterization of tensile behavior and aging resistance of Zr-modified SAC105 solder alloy.

In this study, 0.2 wt% zirconium (Zr) added Sn–1.0Ag–0.5Cu (SAC105) lead-free solder alloy was prepared and its microstructure, tensile property, and aging stability were investigated and compared with the original SAC105 solder alloy. The SAC105 and SAC105-0.2Zr solder alloys were fabricated by vacuum induction melting method. The results showed that the Zr-added SAC105 solder exhibited a significantly refined microstructure. The primary β-Sn phases, Ag₃Sn particle size, and spacing of Ag₃Sn had been obviously reduced with the addition of trace amounts of Zr. The tensile test demonstrated that both strength and elongation of the SAC105-0.2Zr solder improved because of the finer microstructure. Isothermal aging was performed at 180 °C for 36 h, 84 h, and 156 h. The existence of Zr could significantly inhibit the coarsening of the Ag₃Sn phases, thus enhancing the microstructure stability under severe aging conditions. Moreover, the Zr-added SAC105 solder showed significant decrease in supercooling, but the melting range was almost unchanged. [ABSTRACT FROM AUTHOR]