Microstructures, interface reaction, and properties of Sn–Ag–Cu and Sn–Ag–Cu–0.5CuZnAl solders on Fe substrate

In this paper, microstructures, interface reaction, and stress–strain response of Sn–3.8Ag–0.7Cu and Sn–3.8Ag–0.7Cu–0.5CuZnAl solders on Fe substrate were investigated systematically. The interface reaction and the growth behavior of FeSn 2 intermetallic compounds (IMC) at two solder joints interface after 250 °C soldering with 1 min, 10 min, and 60 min are shown. The results indicate that the growth rate of FeSn 2 IMC of Sn–3.8Ag–0.7Cu/Fe solder joints was higher than that of Sn–3.8Ag–0.7Cu–0.5CuZnAl/Fe solder joints, the addition of 0.5% CuZnAl particles can decrease the growth rate of interfacial FeSn 2 IMC layer with the reduction of elements diffusion coefficient. Based on finite element simulation, it is demonstrated that the addition of CuZnAl particles can decrease the von Mises stress and equivalent creep strain of Sn–3.8Ag–0.7Cu/Fe solder joints, due to the decrease of FeSn 2 thickness with the addition of CuZnAl particles, which can enhance the reliability of Sn–3.8Ag–0.7Cu/Fe solder joints.