Creep damage is governed by different microstructural features (e.g. precipitate coarsening, substructure growth, cavity/crack nucleation and growth) during long term high temperature exposure in 9–12%Cr steels. The dependences of stress states (e.g. equivalent stress and stress tri-axiality) on these damage mechanisms are clarified in this work. Various stress states are produced in FB2 steel notched components with different root radii for creep tests at 605 °C. Results indicate that equivalent stress and stress tri-axiality present different influences on creep damage behavior of notched components at elevated temperatures. The equivalent stress and stress tri-axiality both enhance the precipitation of the carbide, indicating larger mean diameter and higher area of the precipitates. Meanwhile, the equivalent stress plays a more significant role on the coarsening of the substructure of the material than the stress tri-axiality. Creep cavities are mainly found at several hundred micrometers away from the notch root, which seems to be induced by the combining action of equivalent stress and stress tri-axiality. These microstructural degradation can be proved by the distribution of the hardness in the notch region of component accompanied by the variation of stress states.

在9-12％Cr的钢中，长期长期暴露于高温下，蠕变损伤受不同的微结构特征（例如，析出物粗化，子结构生长，型腔/裂纹成核和生长）的控制。这项工作阐明了应力状态（例如等效应力和应力三轴性）对这些破坏机制的依赖性。在605°C下进行蠕变测试时，具有不同根半径的FB2钢缺口构件会产生各种应力状态。结果表明，当量应力和三轴应力对高温下缺口构件的蠕变损伤行为有不同的影响。等效应力和应力三轴性都增强了碳化物的析出，表明更大的平均直径和更大的析出面积。与此同时，与应力三轴性相比，等效应力在材料亚结构的粗化中起着更重要的作用。蠕变腔主要在距缺口根部几百微米处发现，这似乎是由于等效应力和应力三轴性的共同作用所致。这些微观结构的劣化可以通过在部件的缺口区域中的硬度分布以及应力状态的变化来证明。