Decouple the effect of the horizontal and vertical components of the collision velocity on interfacial morphology in electromagnetic pulse welding

The morphologies of the interfaces in electromagnetic pulse welding joints have a significant impact on their bonding strength and have therefore garnered attention from researchers. In this study, a hydrodynamic model was developed to systematically analyze the effects of the horizontal and vertical components of the impact velocity on the interface morphology and evolution during electromagnetic pulse welding. An experimental platform with a capacity of 28 kJ/20 kV was constructed and utilized to perform unidirectional and bidirectional collision welding on Al-Cu and Al-Al joints. The simulation results accurately predicted the presence of straight, wavy, and vortex interfaces, which were verified through scanning electron microscopy. The results showed that the interfacial shear instability is primarily influenced by the horizontal component of the two plates at the interface, while the vertical component has a stabilizing effect. When the vertical component is consistently held at 300 m/s, the behavior of the interface undergoes a notable transition as the horizontal component increases. Starting at 40 m/s, the interface presents a straight form with waves. But as this speed advances towards 150 m/s, it transitions to a distinct wavy pattern punctuated by wakes. This dynamic evolves even further when the horizontal speed reaches 300 m/s, at which point a vortex formation becomes evident. This research provides insights into the formation and evolution mechanisms of interface morphologies in electromagnetic pulse welding and guides the adjustment of welding process parameters.