Abstract Two competing failure modes, namely inclusion- and matrix-driven failures, are studied in a Ni-base superalloy, RR1000, subjected to fatigue loading using crystal plasticity finite element (CPFE) simulations. Each individual factor related to the inclusion, which may contribute to crack initiation, is isolated and systematically investigated. Specifically, the role of the inclusion stiffness, loading regime, loading direction, a debonded region in the inclusion-matrix interface, microstructural variability around the inclusion, inclusion size, dissimilar coefficient of thermal expansion (CTE), temperature, residual stress, and distance of the inclusion from the free surface are studied in the emergence of two failure modes. The CPFE analysis indicates that the emergence of a failure mode is an outcome of the complex interaction between aforementioned factors. We observe the possibility of a higher probability of failure due to inclusions with increasing temperature, if the CTE of the inclusion is higher than the matrix, and vice versa. We do not find any overall correlation between the inclusion size and its propensity for damage, based on an inclusion that is of the order of the mean grain size. Finally, the CPFE simulations indicate that the surface inclusions are more damaging than the interior inclusions for similar surrounding microstructures.

中文翻译：

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镍基高温合金中夹杂物和基体驱动的竞争失效模式的晶体塑性评估

摘要 使用晶体塑性有限元 (CPFE) 模拟在承受疲劳载荷的镍基高温合金 RR1000 中研究了两种相互竞争的失效模式，即夹杂物和基体驱动的失效。与夹杂物相关的每一个可能导致裂纹萌生的单独因素都被隔离和系统地研究。具体而言，夹杂物刚度的作用、加载方式、加载方向、夹杂物-基质界面中的脱粘区域、夹杂物周围的微观结构变异性、夹杂物尺寸、不同的热膨胀系数 (CTE)、温度、残余应力和距离在两种失效模式的出现中研究了来自自由表面的夹杂物。CPFE 分析表明故障模式的出现是上述因素之间复杂相互作用的结果。如果夹杂物的 CTE 高于基体，我们观察到由于夹杂物随温度升高而导致失效概率更高的可能性，反之亦然。根据平均晶粒尺寸数量级的夹杂物，我们没有发现夹杂物尺寸与其损坏倾向之间存在任何整体相关性。最后，CPFE 模拟表明，对于类似的周围微观结构，表面夹杂物比内部夹杂物更具破坏性。根据平均晶粒尺寸数量级的夹杂物，我们没有发现夹杂物尺寸与其损坏倾向之间存在任何整体相关性。最后，CPFE 模拟表明，对于类似的周围微观结构，表面夹杂物比内部夹杂物更具破坏性。根据平均晶粒尺寸数量级的夹杂物，我们没有发现夹杂物尺寸与其损坏倾向之间存在任何整体相关性。最后，CPFE 模拟表明，对于类似的周围微观结构，表面夹杂物比内部夹杂物更具破坏性。