Characterization of intergranular corrosion defects in a 2024 T351 aluminium alloy

Abstract

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.

On the Global and Localised Corrosion Behaviour of the AA2524-T3 Aluminium Alloy Used as Aircraft Fuselage Skin

“…According to the American Society for Metals 2 the alloys of the 2xxx series are particularly suitable for structural parts that require a high strength-to-weight ratio and are used in the manufacture of aircraft fuselages, aircraft wings and parts needing a good resistance to temperatures below 150 ºC. However, as described by Queiroz et al 7 and Bonfils-Lahovary et al 8 , aluminium alloys have a very complex microstructure due to heterogeneities leading to an increase of localised corrosion.…”

Improvement of corrosion resistance of AA2024-T3 using femtosecond laser peening without protective and confining medium

“…However, AA2024-T3 remains one of the most studied aluminium alloys in the scientific corrosion literature due to its poor corrosion resistance in chloride-containing aqueous environments [3,4]. High corrosion susceptibility to localised corrosion, such as pitting and intergranular corrosion (IGC), originates from its complex heterogeneous microstructure with compositional variation, which leads to strong micro-galvanic coupling between various alloy phases [4][5][6][7][8].…”

“…8 (EDS results of region1 & 2). This is also confirmed by the film resistance Rf, which decreased for the BM sample from 4.74 kΩcm 2 to only /18/ 30.42 Ωcm 2 .…”