To increase efficiency and reduce greenhouse gas emissions, the operating temperatures of combined power plants have increased. As a result, high-pressure turbine (HPT) blades are subjected to increasingly harsh operating conditions, which cause thermo-mechanical fatigue (TMF) damage and reduce the lifetimes of the gas turbine blades. Therefore, accurate analysis of the TMF characteristics caused by various strain and temperature conditions is needed to ensure the integrity and provide accurate lifetime assessments of the components of gas turbines. However, there have been few studies on the TMF characteristics of single crystal Ni-based superalloys, particularly CMSX-4. In this study, the TMF characteristics of a <001 > oriented single crystal Ni-based superalloy CMSX-4, which is used for HPT first-stage rotor blades, were investigated via strain-controlled TMF tests and the fatigue fractogra-phy was observed using scanning electron microscopy. Additionally, the relationship between the fatigue lifetimes of CMSX-4 and IN738LC was evaluated, and the tensile properties and microstructures at different temperature were investigated. Such TMF test results can be useful for analyzing the thermo-mechanical behavior and predicting the lifetimes of blades.

为了提高效率并减少温室气体排放，已提高了联合发电厂的运行温度。结果，高压涡轮机（HPT）叶片经受越来越苛刻的运行条件，这会导致热机械疲劳（TMF）损坏并缩短燃气涡轮机叶片的寿命。因此，需要对由各种应变和温度条件引起的TMF特性进行精确分析，以确保完整性并提供燃气轮机组件的准确寿命评估。但是，关于单晶镍基高温合金，特别是CMSX-4的TMF特性的研究很少。在这项研究中，用于HPT一级转子叶片的<001>取向单晶镍基高温合金CMSX-4的TMF特性，通过应变控制的TMF测试进行了研究，并使用扫描电子显微镜观察了疲劳形貌。此外，评估了CMSX-4和IN738LC的疲劳寿命之间的关系，并研究了在不同温度下的拉伸性能和显微组织。这样的TMF测试结果可用于分析热机械行为并预测叶片的寿命。