Mechanisms and models of oxygen-assisted fatigue crack propagation at high temperature: A review

In high-temperature environments, oxygen may accelerates the initiation and propagation of fatigue cracks. It significantly affects the performance of structures and restricts their service life. Therefore, it is necessary to study the mechanisms by which oxygen diffusion and oxidation affect fatigue crack propagation at high temperatures. To date, although various mechanisms and models for the influence of oxygen on crack propagation have been proposed, a comprehensive review of the subject is still not available. This paper aims to provide an overview of the topic to help readers understand the field. At first, the paper discusses the influencing factors and mechanisms of oxygen-accelerated crack propagation. Secondly, the relevant models are discussed, including mechanism model, the oxygen-assisted fracture model, the crack growth rate model, and the life prediction model. Thirdly, the paper suggests the limitations and the improvement direction of the models.