Planar energetics do not determine twin persistence in nanocrystalline aluminium
Abstract
Planar energetics are the standard descriptors of twinnability in face-centred cubic metals and the usual validation targets for interatomic potentials. Here we show that they do not determine whether deformation twins persist in nanocrystalline aluminium. Two machine-learned potentials reproducing the same zero-load slip curves and closely spaced layered energy surfaces predict, from a common separated-fault precursor under identical loading, retained twin coverage of 64\% and 14\%. The divergence traces to forces within distorted partial cores acting along the trailing translation that would remove an outer fault. Planar energetics do set the margin: an outer fault more than halves the incremental barrier for middle-plane shear, yet twin completion and fault removal remain separated by only 10--21 mJ m\textsuperscript{-2}. Whether an assembled twin persists is decided instead by the orientation of local traction relative to the full-slip bisector and by the arrival order of partial-slip fronts from the grain-boundary network.
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BibTeX
@misc{wu2026planar,
title = {{Planar energetics do not determine twin persistence in nanocrystalline aluminium}},
author = {Yue Wu and Yuan Tian and Haoyu Wan and Deng Pan and Mingwei Chen},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.37925},
eprint = {2610.37925},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.37925},
}
RIS
TY - UNPB
TI - Planar energetics do not determine twin persistence in nanocrystalline aluminium
AU - Yue Wu
AU - Yuan Tian
AU - Haoyu Wan
AU - Deng Pan
AU - Mingwei Chen
PY - 2026
DA - 2026/10/27
PB - arXiv
DO - 10.48550/arxiv.2610.37925
UR - https://arxiv.org/abs/2610.37925
AB - Planar energetics are the standard descriptors of twinnability in face-centred cubic metals and the usual validation targets for interatomic potentials. Here we show that they do not determine whether deformation twins persist in nanocrystalline aluminium. Two machine-learned potentials reproducing the same zero-load slip curves and closely spaced layered energy surfaces predict, from a common separated-fault precursor under identical loading, retained twin coverage of 64\% and 14\%. The divergence traces to forces within distorted partial cores acting along the trailing translation that would remove an outer fault. Planar energetics do set the margin: an outer fault more than halves the incremental barrier for middle-plane shear, yet twin completion and fault removal remain separated by only 10--21 mJ m\textsuperscript{-2}. Whether an assembled twin persists is decided instead by the orientation of local traction relative to the full-slip bisector and by the arrival order of partial-slip fronts from the grain-boundary network.
ER -