Effects of Ultrasonic Vibration on Diffusion Welding of Aluminum(Materials, Metallurgy & Weldability)

The ultrasonic vibration has been applied in the diffusion welding of aluminum in an attempt to break up the superficial oxide film of the bond interface. The ultrasonic vibration and subsequent welding have been carried out in a vacuum of 10-2 Pa at 875 K to 893 K under a welding pressure of 1 to 3 MPa. The bond strength increased with the increase in the input power to the transducer and working time of ultrasonic vibration. The increase in pressure to the bond interface during the vibration, however, lowered the bond strength. TEM observation and electric resistance measurement of the bond interface revealed that the application of ultrasonic vibration had the effect of breaking up and dispersing the oxide film, which was closely related to the increase in bond strength. On the fractured surface of joint, dimple patterns, increased with the rise of bond strength. These portions may be regarded as places where the application of ultrasonic vibration promotes breaking up and dispersing the oxide film.