Dissimilar welding of aluminium to steel: A review

The combination of aluminium (Al) and steel is a promising solution in the automotive industry for reducing the weight of automotive body structure and fuel consumption. The dissimilar welding of Al/steel poses significant challenges because of the formation of intermetallic compounds (IMCs) between iron and aluminium. The article summarizes the formation and growth mechanisms of Fe-Al IMCs. This paper reviews the progress on dissimilar welding of Al/steel by various welding methods, including friction stir welding (FSW), laser welding (LW) and resistance spot welding (RSW). This paper focuses on the joining mechanisms, interlayer materials, microstructure and mechanical properties associated to each method. The influence of process parameters, tool geometry, composition of the filler material, joint type, composition of the interlayer or coating, RSW with cover plate and external energy fields on the microstructure and mechanical properties of the joint is also reviewed. In addition, the temperature control range of Al/steel interface for various welding processes is summarized systematically. Furthermore, several suggestions for further research directions on the dissimilar welding of Al/steel are provided.