LAUSR

Abstract The brittle Sn58Bi solder was modified with the ductile copper foam (Cu-F) with high plasticity to improve its mechanical properties. It is observed that the coarse microstructure of Sn58Bi solder is notably refined by the uniform distribution of copper foam. Moreover, it is found that the shear force of Sn58Bi soldered sample increases sharply with increasing shear distance and brittle fracture occurs once the shear force reaches the maximum value. However, thanks to the existence of large amount of copper frameworks in Sn58Bi + Cu-F soldered sample, significant plastic deformation is generated after reaching the maximum shear force and no fracture is observed. Also, the Sn58Bi + Cu-F soldered sample demonstrates a higher resistance to elastoplastic deformation as the average maximum indentation depth decreases from 2.48 μm to 1.80 μm compared to the Sn58Bi solder. In addition, the creep of soldered samples becomes stable after 200 s, and a lower creep rate is gained in Sn58Bi + Cu-F soldered sample.