The dissolution mechanism of S-phase particles in 2024-T351 aluminum alloy at open-circuit potential in chloride-containing sulfate solutions was investigated using atomic force microscopy ͑AFM͒, scanning Kelvin probe force microscopy ͑SKPFM͒, and secondary ion mass spectroscopy ͑SIMS͒. The combination of the three techniques allowed the correlation between SKPFM measurements and the corrosion behavior of AA2024 to be confirmed, leading to a better understanding of the electrochemical behavior of S-phase particles. A three-step mechanism for the dissolution and accompanying processes occurring near S particles was proposed: ͑i͒ preferential aluminum and magnesium dissolution, ͑ii͒ galvanic coupling between the copper-enriched particles and the surrounding matrix, leading to an increased passivity of the matrix around the particles, and ͑iii͒ copper deposition around the corroded particles.

The corrosion behavior of a Friction Stir Welding joint in 2050-T3 Al-Cu-Li alloy was studied in 1 M NaCl solution and the influence of T8 post-welding heat treatment on its corrosion susceptibility was analyzed. After exposure to 1 M NaCl solution, the heat affected zone (HAZ) of the weld without post-welding heat treatment was found to be the most extensively corroded zone with extended intergranular corrosion damage while, following T8 post-welding heat treatment, no intergranular corrosion was observed in the HAZ and the global corrosion behavior of the weld was significantly improved. The corrosion damage observed on the welded joints after immersion in 1 M NaCl solution was compared to that obtained after 750 h Mastmaasis Wet Bottom tests. The same corrosion damage was observed. Various stationary electrochemical tests were carried out on the global welded joint and/or each of the metallurgical zones of the welded joint to understand the corrosion damage observed. TEM observations helped in bringing meaningful elements to analyze the intrinsic electrochemical behavior of the different zones of the weld related to their microstructure. However, galvanic coupling tests showed that galvanic coupling effects between the different zones of the weld were at least partially responsible for its corrosion behavior. VC 2011 The Electrochemical Society. [DOI: 10.1149/1.3562206] All rights reserved. Manuscript submitted September 21, 2010; revised manuscript received February 4, 2011. Published March 23, 2011. When dealing with the design of metal aircraft structures, manufac-turers have explored several solutions to reduce both the weight an

A statistical study combining atomic force microscopy, scanning Kelvin probe force microscopy ͑SKPFM͒, and energy-dispersive spectroscopy was carried out on more than 300 Al 2 CuMg intermetallic particles of AA2024 alloy to determine their corrosion behavior in chloride-containing solutions. The combination of these three techniques allowed the correlation of the dissolution depth of the S-phase particles to their SKPFM potential and their chemical composition. This study also revealed that SKPFM measurements must be carried out with many precautions, but it is a powerful tool for the study of localized corrosion.