Ultrasonic welding of metals

The ultrasonic welding of metals is now a well established technique. But the physical principles are still not clearly understood. In this paper, the author suggests that two physical mechanisms operate and that their effects can be distinguished in ultrasonically produced welds. The paper also includes a description of the techniques available for coupling shear vibration to workpieces and a brief up-to-date review of the performance and applications of ultrasonic welders. The paper is an expanded version of a lecture given in the course “Aspects of joining metals” at Sir John Cass College, London, in April 1965