Creep–fatigue experiments were performed at 850℃ on bare and salt-coated directionally solidified Ni-based superalloy DZ125. Experimental test results showed that the salt-coated sample exhibited lower lifetime than that of the bare sample under all stress conditions. This reduction is found to correlate directly with the higher probability of crack initiation, due to surface micro-structural degradation and higher actual stress as a result of the decrease in effective bearing area. A modified damage accumulation model considering the creep, fatigue, and hot-corrosion interaction effect was proposed to predict the corrosion–creep–fatigue lifetime. In this model, a critical high-temperature hot-corrosion exposure time was proposed and was introduced using the Miller linear damage accumulation model. The predicted lifetimes correspond remarkably well with the experimental results.

中文翻译：

---

高温热腐蚀对定向凝固镍基高温合金蠕变疲劳行为的影响：机理和寿命预测

蠕变疲劳试验是在 850℃ 下对裸露和盐涂层定向凝固镍基高温合金 DZ125 进行的。实验测试结果表明，在所有应力条件下，盐涂层样品的寿命都低于裸样品。发现这种减少与更高的裂纹萌生概率直接相关，这是由于有效承载面积减少导致表面微观结构退化和更高的实际应力。提出了一种考虑蠕变、疲劳和热腐蚀相互作用效应的修正损伤累积模型来预测腐蚀-蠕变-疲劳寿命。在该模型中，提出了临界高温热腐蚀暴露时间，并使用米勒线性损伤累积模型进行了介绍。