A Summary of Corrosion Properties of Al-Rich Solid Solution and Secondary Phase Particles in Al Alloys

Abstract

Abstract:The heterogeneous structure of Al alloys renders them susceptible to localized corrosion due to the different electrochemical properties existing in the Al-rich solid solution matrix and secondary phase particles. The galvanic interactions between these two phases can result in pit formation either through dissolution of the particles or corrosion of the matrix adjacent to the particles. This detrimentally localized corrosion behavior is closely related to the corrosion properties of the particles and the Al-rich matrix. The comprehensive characterization of this behavior under various and varying conditions is critical to understanding the mechanism of pit formation, selecting appropriate inhibitors, and developing protection strategies. The corrosion properties (corrosion potential, pitting potential and corrosion rate) of both secondary phase particles and Al-solid solutions in Al alloys are summarized in this review, aiming to provide a database for corrosion research applicable to the localized corrosion of Al alloys.

Influence of Aerospace Standard Surface Pretreatment on the Intermetallic Phases and CeCC of 2024-T3 Al-Cu Alloy

“…In the case of Al(Cu,Mg) phases with sponge appearance that still remain after Pretreatment 2 present a high reduction in Mg and Al atomic % and an increase in Cu atomic %. These results are in good agreement with other authors [40][41][42] that describe the dissolution of the phase Al(Cu, Mg) in an oxidant or corrosive medium proceeding with an initial dealloying in Mg, followed by other dealloying in Al which produce an enriching of particles in Cu and a final detachment of the Al(Cu,Mg) particles. The dissolution of Mg and Al are justified by the anodic behaviour of this phase against the aluminium matrix.…”

Failure analysis of landing gears strut bearings

“…The galvanic interactions between particles and the matrix can result in pit formation either through dissolution of the particles or corrosion of the matrix adjacent to the particles (18).…”

Stress Corrosion Cracking of Friction Stir-Welded AA-2024 T3 Alloy

“…They are considered to be responsible of the short-term electrochemical behavior of the alloy as it is well-known that the interface between these particles and the matrix is particularly active because of its different practical nobility [30]. The main second phases of AA-2024 T3 alloy are S phases (Al2CuMg) and Al-Cu-Mn-Fe [30,31]. Generally, the formers are anodic with respect to the aluminum matrix because of the presence of magnesium, while the latter, consisting of more noble elements such as copper, iron, and manganese, are cathodic.…”

“…The enriching in copper because of the preferential dissolution of magnesium in S-phase, is responsible for the initial increasing of the OCP, but the rapid activation of corrosion phenomena at precipitate-free zones causes the decrease in the OCP after a few hours of immersion. The main second phases of AA-2024 T3 alloy are S phases (Al 2 CuMg) and Al-Cu-Mn-Fe [30,31]. Generally, the formers are anodic with respect to the aluminum matrix because of the presence of magnesium, while the latter, consisting of more noble elements such as copper, iron, and manganese, are cathodic.…”