Research progress of dissimilar friction stir welding between aluminum and steel

The aluminum/steel heterogeneous composite structures have many advantages,such as light weight,energy saving,cost reduction,and meeting different working conditions,which has attracted more and more attention in aerospace,shipbuilding and other fields.Due to the great differences in the physical and chemical properties between aluminum and steel,the joining of aluminum to steel becomes a difficult problem in welding fields.As a solid-state welding method,friction stir welding with low heat input,short residence time at high temperature and small welding deformation,has advantages to overcome the welding difficulties caused by the different performance of aluminum/steel dissimilar alloys.Friction stir welding has become a hot research topic in the aluminum/steel dissimilar alloys welding.In this paper,the current research status of friction stir welding of aluminum/steel dissimilar alloys was reviewed,which mainly deals with the selection of the tool materials and structure design,weld formation,welding process window,mechanical properties,joint metallurgical bonding,joining mechanism and external assisted friction stir welding,which can provides a new idea for the lightweight design of aluminum/steel heterogeneous structure.Finally,the development trend of the joining for aluminum/steel heterogeneous structure was forecasted.