Oxygen-assisted cracking behavior model based on phase-field fracture framework

Oxidation can have a major effect on the crack growth behavior of components working at high temperatures. However, phase-field (PF) fracture models considering oxidation are lacking. This study proposes a PF framework specifically designed for oxygen-assisted cracking. The model builds on the dynamic embrittlement behavior caused by oxygen, and an oxygen-related fracture-toughness degradation function is established. Then, this model is extended to fatigue, creep, and creep-fatigue cracks by employing the corresponding PF model. The model is validated using several examples. Specifically, (i) fatigue cracks for compact tension specimens, (ii) creep cracks for compact tension specimens, and (iii) creep-fatigue cracks for compact tension and shear specimens are simulated. The simulation results are consistent with the experimental results, proving the predictive ability of the proposed framework.