Corrosion Development in Welded AA6082 Alloys
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AlMgSi alloys, frequently used as extruded profiles, generally show excellent corrosionresistance, as Mg is incorporated in the protective oxide layer, thus providing additionalstabilization. However, localized corrosion forms such as intergranular corrosion (IGC)and pitting corrosion may occur as a result of improper heat treatment or unfortunate alloying composition.In this study, four variants of AA6082 have been subjected to an accelerated IGC test in addition to Cyclic Acidified Synthetic Sea Water (Fog) Testing (SWAAT). Moreover,the effects of welding on corrosion behaviour have been examined,and alloys have been subjected to both MIG welding, friction stir welding (FSW) and weld simulation. The effect of Cu content and ageing on the susceptibility to IGC and pitting corrosion have also been studied. Results from this study revealed significant pitting corrosion on all variants, and the severity was found to increase with increasing Cu content and ageing time. Moreover, the heat affected zone of samples welded by FSW and MIG displayed higher corrosion resistance as compared to the weld and the base metal. Despite such observations, no significant variation in corrosion potential as a function of distance from the weld could be observed.