Study on the microstructure and mechanical properties of Cu-Sn intermetallic joints rapidly formed by ultrasonic-assisted transient liquid phase soldering

The microstructure and mechanical properties of complete intermetallic joints rapidly formed by the ultrasonic-assisted transient liquid phase (TLP) soldering process were investigated. Compared to the intermetallic joints formed by the traditional TLP soldering process, the resulted intermetallic joints consisted of remarkably refined Cu6Sn5 grains, with an average size of 3.5 μm. They also demonstrated more uniform mechanical properties with elastic modulus and hardness values of approximately 123 GPa and 6.0 GPa, respectively, as well as higher reliability, in terms of higher shear strength of 60.1 MPa. These results provided a new insight into the effects of ultrasonic on the microstructures and properties of intermetallic joints.