FIB/SEM study of AA2024 corrosion under a seawater drop, part II

• Published in: Corrosion science 2012-02, Vol.55, p.116-125
• Main Authors: King, Peter C., Cole, Ivan S., Corrigan, Penny A., Hughes, Anthony E., Muster, Tim H., Thomas, Sebastian
• Format: Article
• Language: English
• Subjects: A. Alloy; A. Aluminium; Aluminum base alloys; Applied sciences; B. SEM; B. TEM; C. Atmospheric corrosion; Clusters; Copper; Corrosion; Corrosion environments; Dissolution; Droplets; Exact sciences and technology; Metals. Metallurgy; Scanning electron microscopy; Sea water
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/j.corsci.2011.10.012

► Dealloying has a directional nature, exhibits banding. ► Oxidation state of copper in sponge remnants found to be variable. ► Dissolution and breakdown of copper sponge structure observed. ► Crystalline defects imaged in dealloyed S-phase. The dissolution of S-phase clusters in aluminium alloy 2024 (AA2024) exposed to a 0.5μl seawater droplet is presented. Foils for transmission electron microscopy (TEM) were made from local attack sites using a focussed ion beam/scanning electron microscope (FIB/SEM). The sections showed that clusters of S-phase particles underwent dealloying. The resulting copper sponge morphology, banding, preferred orientation and crystal defect structure as a result of plastic deformation have been characterised. With build-up of amorphous corrosion product, physical and electrical isolation of parts of the clusters developed, with the result of copper dissolution from the S-phase remnants.