Interfacial microstructures and mechanical properties of Sn–9Zn–0.5Ga–xNd on Cu substrate with aging treatment

• First discovered the combined action of Ga and Nd.
• First discovered that no Sn–RE phase formed in SZG-Nd solder after aged for 1200 h.
• The shear force of solder joint is greatly improved after aged over 1200 h.

The interfacial microstructures and mechanical properties of Sn–9Zn–0.5Ga–xNd on Cu substrate with aging treatment were investigated. Unlike the previous results, no Sn–RE phase was formed near the interface of Sn–9Zn–0.5Ga–xNd soldered joint after aging treatment at 150 °C for 1200 h. The combined action of Ga and Nd inhibited the formation of Sn–RE phase and resulted in an enhanced reliability of the soldered joint. The shear force of Sn–Zn–0.5Ga–0.08Nd soldered joint after aging treatment for 1200 h was twice the amount of Sn–9Zn joint and approaching the origin as-soldered joint of Sn–9Zn. Further, the fracture type of soldered joint still performed ductile after aging treatment for 1200 h. Synthesized the results of interfacial microstructures, mechanical test and fracture morphologies, Sn–9Zn–0.5Ga–0.08Nd solder has shown great potential to satisfy the increasing reliability requirements in electronics industry.