Influence of Al7Cu2Fe intermetallic particles on the localized corrosion of high strength aluminum alloys

• The corrosion on new aerospace aluminum alloy is studied.
• Al7Cu2Fe precipitate was detected in the 7475-T7351 and 7081 T73511 alloy by scanning electron microscopy.
• Al7Cu2Fe particles have different morphologies depending on the forming process.
• Corrosion pitting occurs around Al7Cu2Fe precipitates in 7475-T7351 and 7081-T73511 alloys.

The development of aluminum alloys of the Al–Zn–Mg–Cu system is the primary factor that enabled the evolution of aircraft. However, it has been shown that these alloys tend to undergo pitting corrosion due to the presence of elements such as iron, copper and silicon. Thus, the purpose of this study is to evaluate the behavior of the Al7Cu2Fe precipitate in 7475-T7351 and 7081-T73511 alloys based on microstructural characterization and polarization tests. The corrosion and pitting potentials were found to be very similar, and matrix dissolution occurred around the Al7Cu2Fe precipitate in both alloys, revealing the anodic behavior of the matrix.