Mechanical Properties and Pitting Corrosion of Friction Stir Welded Aluminium Alloy 5083 (H321)

In the present work, 6 mm plates of Al-Mg alloy AA5083-H321 was friction welded. Weld microstructures, hardness values and tensile properties were evaluated in the welded condition. Macrostructure studies revealed that the shape of the stir zone is a basin-shaped type and it appeared more like a rectangular box and no macroscopic defect or weakly bonded regions were observed in the weld region, which extended through the full thickness of the plates. There were no noticeable changes in the microstructure compared to the respective unaffected base material and there was not much of difference in the microstructures of the nugget and the base metal. The pitting corrosion results indicate that there was noticeable improvement in the pitting potential values of the welds. The weld nugget region exhibited better pitting corrosion resistance compared to other regions. The base material and the friction stir welded materials are far superior in resistance to salt fog corrosion.