Feasibility and Mechanistic Analysis of 3-Stack Aluminium-Steel Spot Joints Using Vaporizing Foil Actuator Welding with Partial Pre-Forming

Abstract

The advancement of spot joining techniques is crucial for automotive manufacturing, yet integrating aluminum-steel (Al-Fe), combinations presents inherent challenges. Traditional methods, such as resistance spot welding (RSW), often lead to the formation of brittle intermetallic compounds (IMCs) and residual stresses, compromising joint integrity. Innovative strategies that enhance mechanical performance while optimizing weight are essential for multi-material assemblies. Advanced techniques like vaporizing foil actuator welding (VFAW) offer a promising solution, enabling metallurgical bonding with minimal heat-induced damage, thereby reducing residual stresses and improving structural relia bility. This study investigates the feasibility of fabricating a 3-stack (Al-Fe-Fe) spot joint using VFAW, employing partial pre-forming of intermediate plates to achieve single-step joining. Smoothed particle hydrodynamics (SPH) modeling is applied to analyze transient stress wave propagation and interfacial jetting dynamics, elucidating their mechanistic influence on interfacial bond formation during high-speed multi-plate interactions. The findings underscore the critical role of partial pre-forming in enabling successful 3-stack VFAW joints.