Formation and mechanical properties of stationary shoulder friction stir welded 6005A-T6 aluminum alloy

• A stationary shoulder tool system used in friction stir welding was developed.
• The defect-free welding joint with gloss surface and small flash was attained.
• The fracture position of welding joint locates in TMAZ.
• High or low heat input is detrimental to mechanical properties of welding joint.

6005A-T6 aluminum alloy is welded by stationary shoulder friction stir welding (SSFSW). At a constant rotational velocity of 2000 rpm, the effect of welding speed on mechanical properties of SSFSW joint are investigated in detail. Defect-free joint with gloss surface and small flash is attained and no cracks appear at the bending angle of 180°. Compared with traditional friction stir welding (FSW), width of rotational shoulder affected zone is relatively small because of the smaller diameter of rotational shoulder. Increasing welding speed is benefit for reducing the width of softening region and the softening degree. The fracture position of welding joint locates in thermo-mechanically affected zone and the fracture surface morphology presents the typical ductile fracture. The maximum tensile strength of joint at the welding speed of 400 mm/min reaches 82% of base metal (BM).