The synergistic combination of mechanical fatigue stresses and environmental agents acting together can be more detrimental than that of the summation of the contributions of each mechanism acting separately. Major attempts to understand the contribution of the different agents (microstructure, chemical composition of environment, temperature, loading conditions, etc.) have been reported in the literature. Nevertheless, current knowledge is insufficient to address life estimation with a sound physical basis from the initiation of localised corrosion (such as pitting) to the estimation of crack propagation. Major simplifications and assumptions have been required in the development of life prediction methodologies. This paper reviews recent efforts made by the different interested parties, in both academia and industry, in the development of corrosion fatigue (CF) lifetime prediction procedures. The paper mainly focuses on the methodologies proposed in the literature for oil and gas, nuclear, energy generation and aerospace applications, dealing with pitting CF damage in aluminium alloys, carbon and stainless steels. The transition of a pit into a small crack (SC) and its growth is influenced by the interaction of the pit stress/strain concentration and the local environmental conditions, making the modelling of this stage of the utmost complexity. A major trend in the models reviewed in this paper is to simplify the analysis by assuming the pit (a volumetric defect) as a sharp crack, decouple the CF problem and account for the mechanical and environmental contributions separately. These procedures heavily rely on fitting experimental data and exhibit low generality in terms of application to varying system conditions. There is a clear opportunity in this field to develop mechanistically based methodologies, considering the inherent dependence of the damage mechanism on the interaction of environmental, metallurgical and mechanical features, allowing more realistic lifetime estimates and defect tolerance arguments, where pit-to-crack transition and SC initiation stages pose a significant challenge.

中文翻译：

---

腐蚀疲劳：损伤容限模型的回顾

机械疲劳应力和环境因素共同作用的协同组合比单独作用的每个机制的贡献总和的组合有害。在文献中已经进行了试图理解不同试剂的贡献的主要尝试（微观结构，环境的化学组成，温度，负载条件等）。然而，从开始局部腐蚀（例如点蚀）到裂纹扩展的估计，当前的知识不足以用合理的物理基础来进行寿命估计。在寿命预测方法的开发中，需要进行重大的简化和假设。本文回顾了学术界和工业界有关各方最近所做的努力，在开发腐蚀疲劳（CF）寿命预测程序方面。本文主要关注文献中提出的针对油气，核能，能源生产和航空航天应用的方法，以解决铝合金，碳和不锈钢中的点蚀CF损伤。凹坑向小裂纹（SC）的过渡及其生长受凹坑应力/应变浓度与局部环境条件的相互作用的影响，从而使该阶段的建模极为复杂。本文所研究的模型的主要趋势是通过假设凹坑（体积缺陷）为尖锐裂纹，简化CF问题并分别考虑机械和环境影响来简化分析。这些过程严重依赖于拟合实验数据，并且在应用于变化的系统条件方面显示出较低的通用性。考虑到损伤机理对环境，冶金和机械特征相互作用的内在依赖性，在该领域中存在明显的机会来开发基于机械的方法，从而可以进行更现实的寿命估计和缺陷容限论证，其中从点到裂纹的过渡SC的启动阶段构成了重大挑战。