Defects and tensile properties of 6013 aluminum alloy T-joints by friction stir welding

• Aluminum alloy T-joints are successfully fabricated by FSW.
• The effect of two kind of corner fillets with different dimensions are analyzed.
• The relationship between tensile properties and welding parameters is investigated.
• Distribution feature of different defects and formation mechanisms are discussed.
• Fracture features of the tensile samples are analyzed.

In this paper, 6013-T4 T-joints were successfully fabricated with different welding parameters by friction stir welding in two different combination modes of skins and stringers. The distribution features and formation mechanisms of defects in T-joints were observed and analyzed. The effect of defects and welding parameters on tensile properties of T-joints was investigated. The result shows that the T-joint without tunnel defect only can be obtained with the traverse speed of 100 mm/min in this experiment, and the welding parameters influence the features and sizes of kissing bond defects. The fracture of T-joints along the shin is attributed to the kissing bond defect and the tunnel defect is the main factor affecting the tensile properties along the stringer.