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Autori principali: Scherer, Jean-Michel, Ramesh, Mythreyi, Bourdin, Blaise, Bhattacharya, Kaushik
Natura: Preprint
Pubblicazione: 2025
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Accesso online:https://arxiv.org/abs/2501.13882
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author Scherer, Jean-Michel
Ramesh, Mythreyi
Bourdin, Blaise
Bhattacharya, Kaushik
author_facet Scherer, Jean-Michel
Ramesh, Mythreyi
Bourdin, Blaise
Bhattacharya, Kaushik
contents The role of grain size in determining fracture toughness in metals is incompletely understood with apparently contradictory experimental observations. We study this grain-size dependence computationally by building a model that combines the phase-field formulation of fracture mechanics with dislocation density-based crystal plasticity. We apply the model to cleavage fracture of body-centered cubic materials in plane strain conditions, and find non-monotonic grain-size dependence of plastic-brittle transgranular fracture. We find two mechanisms at play. The first is the nucleation of failure due to cross-slip in critically located grains within transgranular band of localized deformation, and this follows the classical Hall-Petch law that predicts a higher failure stress for smaller grains. The second is the resistance to the propagation of a mode I crack, where grain boundaries can potentially pin a crack, and this follows an inverse Hall-Petch law with higher toughness for larger grains. The result of the competition between the two mechanisms gives rise to non-monotonic behavior and reconciles the apparently contradictory experimental observations.
format Preprint
id arxiv_https___arxiv_org_abs_2501_13882
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Grain-size dependence of plastic-brittle transgranular fracture
Scherer, Jean-Michel
Ramesh, Mythreyi
Bourdin, Blaise
Bhattacharya, Kaushik
Materials Science
The role of grain size in determining fracture toughness in metals is incompletely understood with apparently contradictory experimental observations. We study this grain-size dependence computationally by building a model that combines the phase-field formulation of fracture mechanics with dislocation density-based crystal plasticity. We apply the model to cleavage fracture of body-centered cubic materials in plane strain conditions, and find non-monotonic grain-size dependence of plastic-brittle transgranular fracture. We find two mechanisms at play. The first is the nucleation of failure due to cross-slip in critically located grains within transgranular band of localized deformation, and this follows the classical Hall-Petch law that predicts a higher failure stress for smaller grains. The second is the resistance to the propagation of a mode I crack, where grain boundaries can potentially pin a crack, and this follows an inverse Hall-Petch law with higher toughness for larger grains. The result of the competition between the two mechanisms gives rise to non-monotonic behavior and reconciles the apparently contradictory experimental observations.
title Grain-size dependence of plastic-brittle transgranular fracture
topic Materials Science
url https://arxiv.org/abs/2501.13882