Phase field numerical model for simulating the diffusion controlled stress corrosion cracking phenomena in anisotropic material

In this study, we develop a phase field numerical model to simulate diffusion-controlled stress corrosion cracking (SCC) in anisotropic materials. Our model is based on multiphysics model involving the electrochemical process, the mechanical response of the material, and the coupling between them. The corrosion system consists of a metallic solid phase immersed in an electrolyte, initially protected by a passive film. The model captures the breakdown of this film, leading to localized pitting corrosion, which subsequently evolves into stress corrosion cracking under the influence of mechanical stress. We employ the Allen-Cahn equation to describe the evolution of the non-conserved phase field variable, representing the metal-electrolyte interface, and the Cahn-Hilliard equation to account for the concentration field dynamics, ensuring volume conservation. The mechanical behavior of the anisotropic material is modeled using crystal plasticity, which accounts for the elastic and plastic deformation of the material, with the degradation due to corrosion incorporated into the stress-strain relationship. We analyze the transition from pitting to cracking in single crystalline, bi-crystalline, and polycrystalline structures. The results demonstrate the capability of the model to capture the complex interactions between electrochemical corrosion and mechanical deformation, providing insights into the pit-to-crack transition in anisotropic materials. The developed phase field numerical model presents a significant advancement in understanding and simulating SCC phenomena, with potential applications in various engineering fields where corrosion is a critical concern.