Quantifying microscale drivers for fatigue failure via coupled synchrotron X-ray characterization and simulations
Quantifying microscale drivers for fatigue failure via coupled synchrotron X-ray characterization and simulations
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DOI：
10.1038/s41467-020-16894-2
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发表时间：
2020-06-24
影响因子：
16.6
通讯作者：
Sangid, Michael D.
中科院分区：
文献类型：
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作者：
Gustafson, Sven;Ludwig, Wolfgang;Sangid, Michael D.
在循环加载过程中，晶内变形由于晶体滑移的本地化作为裂纹萌生的前兆，往往在相干孪晶界。一套高分辨率的同步辐射X射线表征，再加上晶体塑性模拟，进行了多晶镍基高温合金显微组织附近的母孪晶界，以了解这种关键的，3D微观结构配置的变形局部化行为。暗场X射线显微镜空间上连接到高能量X射线衍射显微镜和X射线衍射对比度断层扫描，以量化，与尖端的分辨率，一个晶粒内的取向差和高弹性应变梯度附近的孪晶界。这些观察结果量化了多晶微观结构中存在的极端亚晶粒尺度应力梯度，这通常导致疲劳失效。
During cyclic loading, localization of intragranular deformation due to crystallographic slip acts as a precursor for crack initiation, often at coherent twin boundaries. A suite of high-resolution synchrotron X-ray characterizations, coupled with a crystal plasticity simulation, was conducted on a polycrystalline nickel-based superalloy microstructure near a parent-twin boundary in order to understand the deformation localization behavior of this critical, 3D microstructural configuration. Dark-field X-ray microscopy was spatially linked to high energy X-ray diffraction microscopy and X-ray diffraction contrast tomography in order to quantify, with cutting-edge resolution, an intragranular misorientation and high elastic strain gradients near a twin boundary. These observations quantify the extreme sub-grain scale stress gradients present in polycrystalline microstructures, which often lead to fatigue failure.