Mechanical and Corrosion Behaviour of Friction Stir Welded 5083-6061 Aluminium Alloy Joints: Effect of Base Material Position

This study investigated the mechanical and corrosion properties of friction stir welded (FSWed) dissimilar AA5083-AA6061 joints by interchanging base material position on the advancing side (AS) and retreating side (RS). The dissimilar joints were also compared with FSWed similar joints of both base materials. The macrostructural images revealed that material mixing patterns in FSWed joints varied greatly depending on where the base metals were positioned. Results indicated that the mechanical and corrosion properties obtained at the stir zone were higher for the given aluminium alloys when placing AA5083-H111 on the AS and AA6061-T6 on the RS. AA5083-AA5083 joint fractured near the centre of the weld, while fractures in all other joints occurred in the heat-affected zone towards the AA6061 side alloy. Corrosion tests showed that dissimilar FSWed joint stir zone regions showed lower corrosion resistance than similar joints. In dissimilar joints, corrosion was initiated from the FSWed borderline and around intermetallic particles precipitated on the AA6061 side.