Effect of environment's aggressiveness on the corrosion damage evolution and mechanical behavior of AA 2024‐T3

Abstract

The aim of this work is to contribute on establishing correlations between corrosion damage from accelerated laboratory corrosion tests of varying aggressiveness; by accounting for both, the metallographic features of corrosion damage and the mechanical properties of the corroded material. The work is based on the investigation of corrosion damage caused by the exposure of 2024‐T3 aluminum alloy to 3.5% NaCl solution, which is presently considered to properly represent in‐service exposure. Corrosion damage evolution was quantified for periods ranging between 500 and 3000 hours by evaluating pitting density, depth, and diameter. It was compared to available results of corrosion damage of the same alloy subjected to exfoliation corrosion test. Furthermore, the tensile properties of precorroded material in each solution were evaluated. The results allow the formulation of correlation functions between corrosion damage geometrical metallographic features from low‐ to high‐aggressiveness environment exposures. On the other hand, the degradation of tensile properties, and particularly of tensile ductility, is more pronounced in specimens exposed to higher corrosion rate environments, even when damage in both environments leads to equivalent metallographic features. This suggests significant differences in the underlying physical mechanisms of the damage accumulation process when the same material is exposed to different corrosive solutions. This work suggests the need to expand current corrosion damage interpretation, to account not only for geometrical metallographic features but also for mechanical properties of the affected material.