Welding between aluminum alloy and steel sheets by using transition joints

Hybrid car bodies can be used to exploit the comparative advantages of steels and aluminum alloys for car lightweighting. This development hinges on the deployment of effective hybrid joining technologies. Hybrid welding with transition joints between 1.35-mm-thick DP1000 dual-phase steel sheets and 2.5-mm-thick 6106 aluminum alloy sheets is here investigated. The transition joints are fabricated by explosion welding, with a titanium interlayer. The aluminum alloy sheet, the transition joint and the steel sheet are butt joined by arc welding, with appropriate fillers. The overall tensile strength of the hybrid joint is about two-thirds of the tensile strength of the homologous arc-welded joint fabricated by using the same aluminum alloy sheet, and it is not significantly affected by corrosion in still synthetic seawater.