An intermittent pattern is observed in the modeling of interfacial cyclic-loading crack growth at high-angle grain boundaries in ternary Fe-Ni-Cr alloys. Different from conventional wisdom of stress-intensity factor, the abrupt crack advances are found driven by extreme value statistics - namely, the aggregation of atoms with most compressive residual stresses. In addition, inherently non-affine atomic stress fluctuations are discovered, and the fluctuations peak at intermediate level of chemical heterogeneity, causing the fastest crack growth. Implications of such nonmonotonic mechanism in regard to the origin of intermediate-temperature embrittlement phenomena are also discussed.
Y. Wang et al., "Nonmonotonic Effect Of Chemical Heterogeneity On Interfacial Crack Growth At High-angle Grain Boundaries In Fe-Ni-Cr Alloys," Physical Review Materials, vol. 7, no. 7, article no. 073606, American Physical Society, Jul 2023.
The definitive version is available at https://doi.org/10.1103/PhysRevMaterials.7.073606
Electrical and Computer Engineering
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01 Jul 2023