Quantifying microscale drivers for fatigue failure via coupled synchrotron X-ray characterization and simulations

Public Time: 2020-06-24 00:00:00
Journal: Nature Communications
doi: 10.1038/s41467-020-16894-2
Author: Sven Gustafson;Wolfgang Ludwig;Paul Shade;Diwakar Naragani;Darren Pagan;Phil Cook;Can Yildirim;Carsten Detlefs;Michael D. Sangid
Summary: 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.
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