Modelling intermetallic phase growth during high-power ultrasonic welding of copper and aluminum

An analytical model was developed to understand the rapid growth mechanism of intermetallic compounds (IMC) interlayer in high-power ultrasonic welding process. The analytic solution was derived for the relationships among welding time, interface temperature and vacancy concentration. The effectiveness of this model was tested by comparing the predicted thickness with the experimental value for high-power ultrasonic welding of copper and aluminium at various amplitudes. The consistency of the comparison demonstrates the accuracy of the model has been improved by considering the dynamic change process of vacancy concentration. Besides, the effects of vibration amplitude and resistance heat on the increasing of the intermetallic thickness have been investigated independently. The results show that the additional heat source could significantly promote the process of ultrasonic welding.