Prediction of crack propagation under cyclic loading based on hydrogen diffusion

Previous work on corrosion fatigue of steel has shown that the crack propagation rate is related to ΔK, Kmax and loading frequency f, in which it can be described in a form of the Paris Law. In current study, fracture mechanics has been employed to explore the hydrogen diffusion effect on crack propagation under cyclic loading. In particular, H potential, diffusivity and hydrostatic stress near crack tip, and the critical loading frequency have been considered in the new model. The predicted crack propagation values have been compared with experimental results of X-65 steel in C-2 and NOVATW solutions, and X-52 steel in C-2 solution and the new model provides physical meanings to rationalize the empirical Paris Law.