Intergranular corrosion of AA6082 Al–Mg–Si alloy extrusion: The influence of trace Cu and grain boundary misorientation

In the present work, the influence of trace level Cu on intergranular corrosion (IGC) in AA6082 Al–Mg–Si alloy is studied using correlative accelerated corrosion testing and high resolution electron microscopy. Further, grain boundary structure and its correlation to IGC are also investigated using electron backscatter diffraction (EBSD) and transmission Kikuchi diffraction (TKD). It is found that in AA6082-T6 alloy with very low Cu content (0.06 wt%), about 13% of high angle grain boundaries have Al2Cu precipitates, which promotes IGC at the grain boundaries.