Research progress of fusion welding of 7xxx high strength aluminum alloys

According to research status of 7xxx high strength aluminum alloy welding, it was mainly introduced from four kinds of fusion welding process including TIG, MIG, laser welding and laser-arc hybrid welding. The problems existed in fusion welding process of 7xxx high strength aluminum alloy were described in detail from aspects of welding defects, formation of weld, softening of welded joints, fatigue property and corrosion resistance. For TIG, MIG, laser welding and laser-arc hybrid welding of 7xxx high strength aluminum alloy, welding defects and low formation quality of weld and strengthened phase dissolved in welded joints could lead to softening, poor corrosion resistance and low fatigue life of welded joints. Optimizing welding parameters, reducing welding defects and improving formation quality of weld were beneficial to improve softening, corrosion resistance and fatigue life of welded joints. Selecting appropriate welding wire (containing Ti, Zr elements and Er, Sc rare earth elements) could make weld produce precipitation strengthening, fine grain strengthening and solid solution strengthening, which could improve softening problem of welded joints. Selecting appropriate post-welding heat treatment could improve size, shape and distribution of strengthening phase, and also improve softening problem of welded joints, while it could also improve corrosion resistance of welded joints.