Misfit-dislocation hierarchy governs sliding of asymmetric non-CSL grain boundaries
Abstract
Grain boundaries (GBs) strongly affect the mechanical response of polycrystalline materials, yet most atomistic studies have focused on coincidence site lattice (CSL) boundaries. Motivated by in situ atomic-resolution observations, we investigate step-free sliding along asymmetric non-CSL tilt GBs in face-centered cubic (FCC) metals using atomistic modeling. In these incommensurate GBs, a dense array of non-glissile primary misfit dislocations accommodates local interfacial mismatch, whereas a more widely spaced array of glissile secondary misfit dislocations accommodates residual mismatch. Uniform-sliding calculations reveal two distinct quantities: the minimum GB structural periodicity λ, defined by the repeating arrangement of primary GB misfit dislocations, and the slip vector b, corresponding to the minimum displacement-shift-complete translation that restores an equivalent GB structure. Nonuniform sliding proceeds through the glide of secondary GB misfit dislocations, which carry b and transform successive boundary segments between crystallographically equivalent translation states. The characteristic spacing between secondary misfit dislocations defines a longer periodicity Λ. For the representative {331}/{111} GB, each secondary misfit dislocation glides through a thermally activated two-step kink-pair mechanism below the athermal stress, advancing by one structural period λ. These results establish a unified crystallographic and dislocation-based framework for understanding stress-driven sliding in structurally complex asymmetric GBs.
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BibTeX
@misc{ding2026misfitdislocation,
title = {{Misfit-dislocation hierarchy governs sliding of asymmetric non-CSL grain boundaries}},
author = {Kunqing Ding and Yazhuo Liu and Yin Zhang and Lihua Wang and Xiaodong Han and Ting Zhu},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.14673},
eprint = {2609.14673},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.14673},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Misfit-dislocation hierarchy governs sliding of asymmetric non-CSL grain boundaries
AU - Kunqing Ding
AU - Yazhuo Liu
AU - Yin Zhang
AU - Lihua Wang
AU - Xiaodong Han
AU - Ting Zhu
PY - 2026
DA - 2026/09/28
PB - arXiv
DO - 10.48550/arxiv.2609.14673
UR - https://arxiv.org/abs/2609.14673
AB - Grain boundaries (GBs) strongly affect the mechanical response of polycrystalline materials, yet most atomistic studies have focused on coincidence site lattice (CSL) boundaries. Motivated by in situ atomic-resolution observations, we investigate step-free sliding along asymmetric non-CSL tilt GBs in face-centered cubic (FCC) metals using atomistic modeling. In these incommensurate GBs, a dense array of non-glissile primary misfit dislocations accommodates local interfacial mismatch, whereas a more widely spaced array of glissile secondary misfit dislocations accommodates residual mismatch. Uniform-sliding calculations reveal two distinct quantities: the minimum GB structural periodicity λ, defined by the repeating arrangement of primary GB misfit dislocations, and the slip vector b, corresponding to the minimum displacement-shift-complete translation that restores an equivalent GB structure. Nonuniform sliding proceeds through the glide of secondary GB misfit dislocations, which carry b and transform successive boundary segments between crystallographically equivalent translation states. The characteristic spacing between secondary misfit dislocations defines a longer periodicity Λ. For the representative {331}/{111} GB, each secondary misfit dislocation glides through a thermally activated two-step kink-pair mechanism below the athermal stress, advancing by one structural period λ. These results establish a unified crystallographic and dislocation-based framework for understanding stress-driven sliding in structurally complex asymmetric GBs.
ER -