ARTICLE INFO ABSTRACT Keywords:lntergranular corrosion defects formed after a 24h immersion in a 1 M NaCI solution in a 2024-T351 Al alloy were characterized using a combination of electron microscopy techniques. Results showed the dissolution of intergranular Cu-rich precipitates ail along the corroded grain boundaries. Cu species were incorporated inside the amorphous alumina oxide film identified in the corroded grain boundaries leading to the formation of structural defects in the oxide film. A 10-200 nm-thin metallic Cu-rich layer was also observed at the oxide{metal interface and at the tip of the intergranular corrosion defect.