Main application limitations of lead-free composite solder doped with foreign reinforcements

The recent researches have shown that adding an appropriate amount of foreign reinforcements to lead-free solders can improve their wettablity, reduce their melting points, optimize their microstructure, and reinforce their mechanical properties. Moreover, it also inhibits the coarsening and growth of intermetallic compounds (IMC) and matrix microstructure under aging conditions such as high temperature aging or current stressing. However, there are still many limitations in the preparation and practical application of composite lead-free solders. By reviewing the existing research results, this paper summarizes the main problems in the preparation and applications of composite solder and analyzes the future research directions of this field.