Chemical-Induced Degradation of Aerospace Aluminum: Structural Integrity and Corrosion Mitigation Implications

The surface degradation mechanisms of aerospace-grade aluminum alloys exposed to persistent organophosphorus compounds were investigated to assess their impact on material integrity under operational conditions. A combination of long-term laboratory exposure tests using live O-ethyl S-(2-diisopropylaminoethyl) methylphosphonothioate (VX) agents and helicopter-based field trials with chemical simulants was conducted. Surface morphology and chemical composition were analyzed through scanning electron microscopy. Complementary density functional theory (DFT) simulations modeled the adsorption behavior of VX and its hydrolysis intermediates on aluminum oxide surfaces. Experimental observations revealed progressive surface roughening, microcrack formation, localized oxidation, and material loss, consistent with DFT-predicted strong adsorption energies (−2.27 eV) and the formation of stable surface-bound intermediates. The persistence of these adsorbed species was observed even after standard decontamination procedures. These findings provide critical insights into the mechanisms of corrosion initiation under chemical exposure and underscore the necessity for advanced surface protection and decontamination strategies to maintain the structural integrity of aerospace materials.