An anomalous wave formation at the Al/Cu interface during magnetic pulse welding

This paper reports an anomalous wave formation at an Al/Cu bimetallic interface produced by magnetic pulse welding. The mechanism of the anomalous wave formation is investigated using both metallurgical characterization and the interface kinematics. It reveals that the anomalous wave is formed with the combination of the intermediate zone and the interdiffusion zone with a thickness of 70 nm, wherein the intermediate zone is caused by the local melting due to the high shear instability, and the interdiffusion zone is formed below the melting point of aluminum combined with ultrahigh heating and cooling rates of about 1013 °C s−1. A multiphysics simulation of impact welding has been performed, and it is identified that the jetting kinematics and non-uniform distribution of shear strains during high-speed collision enable the formation of the anomalous wave. The numerical and experimental results comprehensively lead to understanding of the mechanism and the characteristics of the anomalous wave produced during an impact welding.