Abstract Inherent defects induced in casting process seriously affect mechanical performance and fatigue properties of the material. Micro-structural investigations reveal that the grain size and dendrite microstructure are sensitive to casting processes and change materials property. The fatigue performance of the material decreases with porosity and is characterized by distributed voids on grain boundaries. Fatigue cracks nucleated from casting defects dominate the whole fatigue failure process. A developed fatigue micro-crack model based on Paris’ law can be used to calibrate low cycle fatigue property of the casting material with different microstructures and agrees with experimental results well.

中文翻译：

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基于断裂力学方法的多孔铸造镍基高温合金疲劳寿命评估

摘要 铸造过程中产生的固有缺陷严重影响材料的力学性能和疲劳性能。微观结构研究表明，晶粒尺寸和枝晶微观结构对铸造工艺和改变材料性能很敏感。材料的疲劳性能随着孔隙率的增加而降低，其特征是在晶界上分布有空隙。由铸造缺陷成核的疲劳裂纹在整个疲劳失效过程中占主导地位。建立的基于巴黎定律的疲劳微裂纹模型可用于标定不同显微组织铸造材料的低周疲劳性能，与实验结果吻合较好。