Investigations on the process window for friction stir assisted double-sided incremental forming with synchronous bonding of steel and aluminum alloy sheets

Dissimilar steel/Al laminates are more widely utilized in lightweight and anti-vibration structures while the preparation and forming processes remain challenging due to obvious difference in materials properties. In this work, separated DC05 and AA5052-H32 sheets are used to fabricate truncated conical laminated parts by a novel pin-less friction stir assisted double-sided incremental forming with synchronous bonding process. The peeling force of formed parts as a metric of bonding strength is evaluated to obtain parameters window based on response surface method. The effects of step down, rotation speed of master tool, wall angle, and their cross terms on bonding strength are investigated. The present work established a functional model to determine optimal parameter combination for better bonding strength. Working temperature and forming force are consistent through process evolution. Optimal solution is also conducted to obtain ultimate forming depth and better surface finish of truncated parts. The findings in this work can help deeply understand the fabrication procedures and thermomechanical results in dissimilar bonding-with-forming processes.