Computational Simulation of Localised Corrosion in Anodised AA 2099-T8 Aluminium-Lithium Alloy

摘要

The initiation of localised corrosion in anodised AA2099-T8 alloy is simulated by using Cellular Automata (CA) method. For CA simulation, the system consisting of corrosive electrolyte, porous anodic alumina film and alloy matrix is described as a 500x300 two-dimensional square lattice. Eight types of cells are defined to construct the cellular space, with the Von Neumann neighbourhood (four cells neighbourhood) being selected. The cellular space is constructed such that a void generated by oxidation of the high-copper-containing Al-Fe-Mn-Cu-Li particle exists in the porous anodic alumina film consisting of a porous layer and a barrier layer. It is suggested that localised corrosion is preferentially initiated in the void defect region in the porous anodic film, which is related to increased corrosion product diffusion rate in this region compared with diffusion in other regions of the porous layer.