Friction stir lap welding of aluminum alloy to advanced high strength steel using a cold-spray deposition as an interlayer

To overcome the undesirable wear of pin-tip during friction stir lap welding (FSLW) of AA6022 aluminum alloy and Usibor® 1500 advanced high strength steel, a precoated Al cold-spray deposition (200 μm in thickness) has been used as the interlayer. The optimized weld shows a simple sandwich-like structure that consists of an aluminum weld, an interface, and a heat affected steel region. No intermetallic compound was found while an Al/Fe diffusion layer with an average thickness of about 10 nm was observed at the deposition/steel interface. No distinct phase transition and mechanical properties change were found in the heat affected steel region.