A probability-based model for growth of corrosion pits in aluminium alloys

Probabilistic growth characteristics of corrosion pits originating from particle clusters present in aluminium alloys is studied in this paper. Towards this, a mechanically driven model, which includes corrosive environment and fatigue load as driving forces, incorporated within a probabilistic framework is proposed and used. Corrosive environment is modelled using related electrochemical variables and temperature while the effect of fatigue load is incorporated by modelling the pits to attain the shape of a prolate spheroid on growth. Discrete probability of particle cluster formation is combined with the pit growth characteristics, which is described in continuous sense, by using the ‘Law of total probability’. Studies conducted using Monte Carlo simulation technique and linear elastic fracture mechanics principles demonstrate the capability of the model to predict an enhanced growth rate of pits under the influence of fatigue load.