Abstract The influence of orientation on the creep rupture properties of nickel-based single crystal superalloy with a center film hole was carried out at 980 °C and 300 MPa. The mechanisms of creep rupture and microstructural evolution of the specimens were studied through macro- and micro-morphological observations and finite element analysis. The central film hole exhibited the creep-strengthening effect on the nickel-based single crystal plate specimens. The degree of strengthening was related to crystal orientations, and the most prominent effect was observed in the [0 1 1] orientation. The steady-state creep rate of the specimens with central film holes decreased in the order of [0 0 1] > [0 1 1] > [1 1 1], which was completely opposite of the specimens without central holes. The creep rupture mechanism occurred due to the growth and aggregation of micro-cracks and voids. The microstructural evolution in the strengthening phase γ’ of the specimens with central film holes was closely related to the local stress state. In the high-stress zone where fractures originated, the rafting directions of the [0 1 1] and [1 1 1] orientations formed a 50° angle with the loading axis, and that of the [0 0 1] orientation was perpendicular to the loading axis. The modified crystal plastic-damage model was employed to perform the analysis of stress and damage around the center hole. The simulation results concorded well with the experimentally observed fracture behaviors.

中文翻译：

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具有中心膜孔的镍基单晶试样的各向异性蠕变断裂机制和微观结构演化

摘要 在980 ℃和300 MPa条件下，研究了取向对带中心膜孔的镍基单晶高温合金蠕变断裂性能的影响。通过宏观和微观形态观察和有限元分析，研究了试样蠕变破裂和微观结构演变的机制。中心膜孔对镍基单晶板试样表现出蠕变强化作用。强化程度与晶体取向有关，在[0 1 1]取向中观察到最显着的影响。具有中心膜孔的试样的稳态蠕变速率以[0 0 1] > [0 1 1] > [1 1 1]的顺序降低，这与没有中心孔的试样完全相反。蠕变破裂机制是由于微裂纹和空隙的生长和聚集而发生的。带中心膜孔的试样在强化相γ'的显微组织演变与局部应力状态密切相关。在裂缝产生的高应力区，[0 1 1]和[1 1 1]方向的漂流方向与加载轴成50°角，[0 0 1]方向的漂流方向与加载轴垂直。加载轴。采用改进的晶体塑性损伤模型对中心孔周围的应力和损伤进行分析。模拟结果与实验观察到的断裂行为非常吻合。带中心膜孔的试样在强化相γ'的显微组织演变与局部应力状态密切相关。在裂缝产生的高应力区，[0 1 1]和[1 1 1]方向的漂流方向与加载轴成50°角，[0 0 1]方向的漂流方向与加载轴垂直。加载轴。采用改进的晶体塑性损伤模型对中心孔周围的应力和损伤进行分析。模拟结果与实验观察到的断裂行为非常吻合。带中心膜孔的试样在强化相γ'的显微组织演变与局部应力状态密切相关。在裂缝产生的高应力区，[0 1 1]和[1 1 1]方向的漂流方向与加载轴成50°角，[0 0 1]方向的漂流方向与加载轴垂直。加载轴。采用改进的晶体塑性损伤模型对中心孔周围的应力和损伤进行分析。模拟结果与实验观察到的断裂行为非常吻合。采用改进的晶体塑性损伤模型对中心孔周围的应力和损伤进行分析。模拟结果与实验观察到的断裂行为非常吻合。采用改进的晶体塑性损伤模型对中心孔周围的应力和损伤进行分析。模拟结果与实验观察到的断裂行为非常吻合。