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Dislocation Core Structure from Diffuse Scattering Below the Bragg Peaks
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DOI：10.1016/j.actamat.2025.121560.png)
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Abstract
En 中文
The characteristics and dimensions of dislocation cores remain a fundamental inquiry in the field of plasticity. Molecular dynamics simulations, along with the regularization of singularities in continuum approaches, can provide valuable insights into core configurations. However, experimental evidence is limited and frequently indirect. In this study, diffuse scattering observed below the Bragg peaks, resulting from narrow distorted core regions, is employed to ascertain the widths of dislocation cores in a highly dislocated Ni-18wt.%Fe nanocrystalline alloy. High-resolution synchrotron X-ray diffraction patterns are analysed to determine dislocation densities, crystallite sizes, and planar defect densities utilizing the Convolutional Multiple Whole Profile line profile analysis technique. A model addressing diffuse scattering from dislocation core material, in conjunction with a cumulative assessment of diffuse scattering associated with thermal diffuse scattering and short-range order, is integrated into the line profile analysis framework. This enhanced method also addresses the singularity at short distances in the Krivoglaz-Wilkens strain function, thereby mitigating the risk of overestimating dislocation densities. The findings indicate that the dislocation core width in the present alloy is approximately 6.7(±0.3) times the Burgers vector length, which aligns well with molecular dynamics simulations and continuum mechanical calculations.
Journal
IF:
9.3
Papers:
2.0W
Citations:
12.9W