A generalised, multi-phase-field theory for dissolution-driven stress corrosion cracking and hydrogen embrittlement

Dear iMechanicians - I hope that the following work is of interest. We oresent the first electro-chemo-mechanical model capable of predicting both hydrogen embrittlement and anodic-dissolution driven stress corrosion cracking. In this way, environmentally assisted cracking predictions can be obtained for any choice of environment and without any 'a priori' decision on the governing mechanism. This allows us to simulate for the first time seminal experiments, such as those by Ghrul on Al alloys. 

A generalised, multi-phase-field theory for dissolution-driven stress corrosion cracking and hydrogen embrittlement
C. Cui, R. Ma, E. Martínez-Pañeda.
Journal of the Mechanics and Physics of Solids 166, 104951 (2022)
https://doi.org/10.1016/j.jmps.2022.104951

We present a phase field-based electro-chemo-mechanical formulation for modelling mechanics-enhanced corrosion and hydrogen-assisted cracking in elastic–plastic solids. A multi-phase-field approach is used to present, for the first time, a general framework for stress corrosion cracking, incorporating both anodic dissolution and hydrogen embrittlement mechanisms. We numerically implement our theory using the finite element method and defining as primary fields the displacement components, the phase field corrosion order parameter, the metal ion concentration, the phase field fracture order parameter and the hydrogen concentration. Representative case studies are addressed to showcase the predictive capabilities of the model in various materials and environments, attaining a promising agreement with benchmark tests and experimental observations. We show that the generalised formulation presented can capture, as a function of the environment, the interplay between anodic dissolution- and hydrogen-driven failure mechanisms; including the transition from one to the other, their synergistic action and their individual occurrence. Such a generalised framework can bring new insight into environment–material interactions and the understanding of stress corrosion cracking, as demonstrated here by providing the first simulation results for Gruhl’s seminal experiments.