Formability of an AA5083 aluminum alloy T-joint using SSFSW on both corners

Abstract

ABSTRACTIn this study, AA5083 aluminum alloy T-joints were properly welded, where both of the corners were successfully joined with stationary shoulder friction stir welding. According to the microstructure, the joint can be divided into base material, heat affected zone, thermo-mechanically affected zone, weld nugget zone and weld nugget overlap zone. The microhardness near the first weld is lower than that near the second weld as a result of the additional heating during the second weld process. In tensile test, the highest tensile strength of the skin and the stringer has reached 50.8% and 56.9% of the base material, respectively. All fractures have occurred near the heat affected zone of the first weld pass, while the fracture mode is ductile. Numerical modeling shows that the maximum strain is located in the area close to the welding tool, and the strain gradient near the advancing side is significantly higher than that near the retreating side. In addition, the degree of material flow is even along the thickness direction of the plate during stationary shoulder friction stir welding, and the material distribution is asymmetric on both sides of the weld due to different material flows in the advancing side and retreating side.