Influences of Ni addition into Cu–xNi alloy on the microstructure evolution and mechanical property of Sn–58Bi/Cu–xNi solder joint

Abstract

In the current investigation, various mass fractions (0, 0.5, 1.5, 5 and 10 wt%) of Ni were doped into Cu substrate, and influences of Ni addition on the microstructure evolution and mechanical property of the Sn-58Bi/Cu-xNi solder joint were investigated. Results showed that the growth rate of intermetallic compound (IMC) would increase with the Ni addition added from 0 to 5 wt% and remarkably decreased for Sn-58Bi/Cu-10Ni joint system. It indicated that the growth rate of IMC layer would decrease when 10 wt% Ni was added into the alloy. Besides, the tensile strength reduced with increase in the IMC thickness, which was under the synergistic effect of increasing liquid-state reaction time and the content of Ni addition (0-5 wt%). Moreover, the fracture mechanism gradually transformed from ductile fracture mode to brittle fracture mode with the decrease in joint strength.