Presentazioni e Articoli Tecnici

Localized corrosion of aluminum alloys remains difficult to predict because conventional electrochemical measurements provide global information, whereas in-service risk is governed by the real morphology of the damage, including pit density, active surface area, local depth, coalescence. This work proposes an original methodology coupling electrochemical measurements with the spatial morphology of corrosion of 2024 T351 aluminum alloy coupling with 316L stainless steel under Volvo-type cyclic environment. The multiphysics modeling of this coupling is performed using COMSOL Multiphysics® to predict the degradation of materials in galvanic coupling. In details, cathodic and anodic kinetics are determined by linear polarization, while morphological observations are processed using a dedicated image-analysis Python algorithm to extract characteristic corrosion morphology parameters. These data are then used to constrain a morpho-Faradaic model linking electrochemical charge, aluminum dissolution, and the experimentally observed material loss. The introduction of morphological coalescence indicators enables the transition from a distributed pit population to a dominant corroded macro-zone to be described. The COMSOL model couples current distribution, electrochemical polarization, species transport in the electrolyte, Faradaic dissolution, morphological evolution and includes a mechanical concentration criterion based on defect localization. The simulation highlights a redistribution of the anodic current on the aluminum surface, a local acceleration of dissolution, and a more severe morphological evolution than that observed for an uncoupled material. The predictions are compared with experimentally extracted dissolved volumes, mass losses, corroded surface areas and characteristic depths. This approach provides a predictive framework linking global electrochemistry to local morphology. It opens the way for a more realistic assessment of the durability of multi-material assemblies, where the critical criterion is not only the total mass loss, but also the localization, depth, and connectivity of corrosion damage.