Chemomechanical finite element analysis for surface oxidation of Aluminum alloy

Metals are prone to oxidation in high-temperature oxygen-containing environments, resulting in oxidative corrosion. This study proposes a fully coupled chemomechanical model and further develops a finite element method (FEM) to characterize the high-temperature oxidation process of metals. Then, we perform finite element analyses for surface oxidation of FeCrAlY alloy to verify the proposed chemomechanical model. Good agreements of FEM results with experimental observations suggest that the model can be used to predict the surface oxidation of metals. The numerical results also reveal the two-way coupling effects between chemical processes and mechanical stress. Furthermore, it is found that compressive stress could inhibit diffusion and chemical reaction in the oxide layer. In contrast, the stress distribution of the oxide layer can also be significantly influenced by compositional strain induced by the concentration change of diffusive species and growth strain induced by chemical reactions. In addition, we find that the barrier effect of alumina on diffusion can significantly slow down the growth of the oxide layer. This study provides an effective model for chemomechanical phenomena and may also shed light on the design of alloys in a request of resistance to oxidative corrosion.