In-Situ Monitoring of Pitting Corrosion in Aluminum Alloy 2024

An in-situ monitoring method was used to observe the initiation sites and the processes of pitting corrosion in aluminum alloy 2024-T3 (UNS A92024) in real time. These observations complemented more detailed information about composition and distribution of constituent particles, pre-and post-corrosion surface morphology, and the internal morphology of corrosion pits. In-situ observations provided a comprehensive view of the development of localized corrosion in real time. Results confirmed the importance of intermetallic constituent particles in promoting initiation and growth of pits in aluminum alloys. Heterogeneous distribution of these particles served to define the location and extent (or severity) of pitting. A conceptual model was proposed as a framework for continued research. The formation of occluded cells under corrosion product domes over severe pits was observed. This formation will be incorporated into an overall reconsideration and modeling of the processes of pitting corrosion of aluminum alloys.