Mechanism of the discharge behavior in electromagnetic pulse welding: Combination of electron emission and electric field

Abstract

The analysis of transient phenomena in electromagnetic pulse welding is of great interest for unraveling the underlying principles. This research systematically investigates the mechanism of the discharge phenomenon by integrating finite element modeling with surface morphology analysis. The results revealed that the discharge area is discretely distributed on the surface, primarily concentrated around the welding area where the severe collision occurs. In contrast, when the collision is eliminated, the discharge is confined only to the edge. Given a fixed input energy, the discharge ablation on the surface is more pronounced for materials with a low work function. The research further establishes that both electron emission and the intense electric field contribute to the discharge behavior. This discharge behavior subsequently leads to high temperatures in the discharge area, facilitating element diffusion and shock wave generation. However, intermetallic compounds are not observed due to the brief duration of the discharge. This study illuminates the adverse effects of the collision and provides profound insights into the dynamic behaviors during welding. The findings offer valuable theoretical guidelines for the development and optimization of welding processes.