Microstructure and mechanical properties of bobbin tool frication stir welded joint of 6005A-T6 aluminum alloy profiles

Bobbin tool frication stir welding butt welded joints were fabricated for 6005A-T6 aluminum alloy profiles with 4.5 mm thickness at higher welding speed. The results show that the welds are excellent both in appearance and properties, but it is more likely to form defects such as tunnel and crack. At the selected welding parameters, the properties of welds shows close relationship with the line energy density, its tensile strength increases with the increase ofWPand reached up to 231 MPa, 77% of the base metal strength at the welding parameters of 1 400 r/min and 1 400 mm/min. The fracture appearance analysis indicates that the fracture mode changes from mixed fracture to ductile fracture with the increase ofWP.