A finite element model for simulating the propagation of intermetallic particle driven micro-galvanic corrosion in an Al-matrix model system is presented. The model revealed dynamic changes related to localized corrosion, including the moving dissolution boundary, the deposition of reaction products (Al(OH) 3 ), and their blocking effect. Modelling was focused on the effects of key geometric parameters, including the radius of cathodic particle (range 0.5 to 4 μm) and the width of an assumed anodic ring surrounding the particle (range 0.1 to 2 μm). Simulations revealed the dynamic flow of molecular and ionic species, along with influence of geometrical constraints. For ring widths below 0.5 μm, deposition of Al(OH) 3 inside the dissolving volume was inhibited due to limited transport of OH − and O 2 into a constrained volume − resulting in local acidification. An increase in cathodic particle radius at given ring width resulted in a greater dissolution by providing a larger cathodic area for O 2 reduction, quantifying the effect of cathode/anode ratio. The model was also developed to include two cathodic particles to explore any interaction. The present study reveals a physicochemical model that contributes toward a framework for multi-process localized corrosion systems, which can be further adapted to commercial alloy systems. The initiation and propagation of different types of localized corrosion are two issues that have been extensively studied for several decades.1-4 An understanding of localized corrosion is important for both corrosion prognosis and corrosion protection. For multi-element alloys with heterogeneous microstructures, local electrochemistry is also heterogeneous, with an attendant risk for localized corrosion when exposed to a corrosive environment. In the case of aluminum (Al) alloys, localized corrosion has been commonly observed to be associated with intermetallic particles (IMPs). [5][6][7][8][9][10][11][12][13][14][15][16] Many alloying additions to Al include more 'noble' elements (i.e. Cu, Fe, Mn, etc.) and such additions leading to IMPs that are termed 'cathodic', resulting in the manifestation of localized corrosion of the alloy matrix surrounding such particles. The imaging of localized corrosion morphologies in a number of Al-alloys has shown that susceptibility and extent of corrosion damage is highly pH dependant. 17,18 Whilst analysis of the morphology of corrosion damage is indeed essential, from the perspective of electrochemical monitoring of localized corrosion, practical limitations of electrochemical measurements make it very difficult to accurately describe the kinetics of the localized corrosion − such as the corrosion induced by heterogeneous microstructures.In response to challenges in directly measuring localized corrosion, recent decades have seen the development of modelling and numerical simulation in the context of rationalising and quantifying the phenomenology of localized corrosion.19-30 Such model can be based on a theoretical analysis of the chemistry and el...