Intergranular corrosion of AA2024-T3: initiation and propagation

AA2024 is a damage tolerant aluminum alloy, which is widely used in aerospace applications. Localized corrosion attack in AA2024 can emerge in the form of pitting corrosion and of intergranular corrosion (IGC). Intergranular corrosion initiation and propagation is the result of a combination of factors (presence of aggressive anions, defects on the protective surface layer, and susceptible grain boundaries) and not solely on the creation of microgalvanic cells between intermetallics and the aluminum matrix. The mechanisms involved in the initiation and propagation of IGC in AA2024-T3 were investigated by means of electrochemical techniques, optical microscopy, SEM and EDS analyses. (author)