现代交通与冶金材料

轨道车辆的涡轮增压器、发动机热端部件、制动系统等高承载部件长期在高温循环载荷下工作。GH4169 是这类部件的核心材料，其蠕变‑疲劳交互作用是导致部件突然失效的主要隐患。为获得关键部件材料在复杂服役条件下的失效判据，以轨道车辆用镍基高温合金 GH4169 为研究对象，在高温服役环境下开展蠕变‑疲劳交互作用试验。在 550~800 ℃范围内设置六个温度点，采用梯形波加载方式施加蠕变‑疲劳交互作用力，分别测试不同温度下合金寿命、蠕变‑疲劳交互曲线和微观形貌。试验结果显示，在 550~650 ℃区间镍基高温合金在蠕变‑疲劳交互作用下寿命较长，蠕变‑疲劳交互作用系数在 650~700 ℃达到峰值，表明该温区两种损伤机制强烈耦合。550~600 ℃时交互作用较弱，符合线性累积损伤模型。断口微观分析显示，550~600 ℃以穿晶疲劳断裂为主；650~700 ℃沿晶断裂比例显著增加，疲劳辉纹与蠕变孔洞共存，γ'/γ″强化相部分溶解；≥750 ℃时完全转为沿晶蠕变断裂，晶粒粗化，孔洞连接成网。

High load components such as turbochargers， engine hot end components， and braking systems of rail vehicles work under high-temperature cyclic loads for a long time. GH4169 is the core material for this type of component. The creep fatigue interaction is the main hidden danger that leads to sudden failure of components. In order to obtain failure criteria for key component materials under complex service conditions， creep fatigue interaction tests were conducted on nickel based high-temperature alloy GH4169 for rail vehicles in high-temperature service environments. Six temperature points were set within the range of 550 to 800 °C， and the creep-fatigue interaction was applied using a trapezoidal wave loading method. The life of the alloy， creep-fatigue interaction curves， and microstructure were tested at different temperatures. The test results show that in the temperature range of 550 to 650 ° C， thenickel-based high-temperature alloy has a longer life under creep-fatigue interaction， and the creepfatigue interaction coefficient reaches its peak at 650 to 700 °C， indicating that the two damage mecha‑nisms are strongly coupled in this temperature range. At 550 to 600 °C， the interaction is weak， which is consistent with the linear cumulative damage model. Microscopic analysis of the fracture shows that at 550 to 600 °C， transgranular fatigue fracture is dominant. At 650 to 700 °C， the proportion of intergranular fracture increases significantly， and fatigue striations and creep holes coexist， with partial dissolution of γ′/γ″ strengthening phase. At ≥750 ° C， it completely turns into intergranular creep fracture， with grain coarsening and the formation of a network of hole connections.