Filling and wetting behaviors of liquid filler metal in the process of ultrasonic soldering of aluminum alloy

Filling of liquid filler metal into the joint clearance of 6061Al and 2024Al alloys under the action of ultrasonic vibration was investigated. The effects of heating temperature and joint clearance value on the filling process were concerned with. The results show that the filling of liquid filler metal under the action of ultrasonic vibration is quite different from that induced by the traditional capillary effect. The non-wetting liquid filler fills rapidly into the joint clearance once the ultrasonic vibration is applied and the morphology of the liquid-gas interface appears convex at the initiate stage. With the development of the filling process, the filling velocity decreases and the wetting between the liquid filler and the base metal at the filling front is improved, giving rise of the transition of the morphology of the liquid-gas interface from convex to concave. Heating temperature shows no obvious influence on the filling process. The filling length decreases and the morphology of liquid-gas interface tend to change with the joint clearance increase.