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Multiphase field modeling of grain boundary migration mediated by emergent disconnections

Gokuli, Mahi and Runnels, Brandon (2021) Multiphase field modeling of grain boundary migration mediated by emergent disconnections. Acta Materialia, 217 . Art. No. 117149. ISSN 1359-6454. doi:10.1016/j.actamat.2021.117149. https://resolver.caltech.edu/CaltechAUTHORS:20210908-225044611

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Abstract

Knowledge about grain boundary migration is a prerequisite for understanding and ultimately modulating the properties of polycrystalline materials. Evidence from experiments and molecular dynamics (MD) simulations suggests that the formation and motion of disconnections is a mechanism for grain boundary migration. Here, grain boundary migration is modeled using a multiphase field model based on the principle of minimum dissipation potential with nonconvex boundary energy, along with a stochastic model for thermal nucleation of disconnection pairs. In this model, disconnections arise spontaneously in the presence of an elastic driving force, and that their motion mediates boundary migration. The effect is due to the fact that the formation of the disconnections pairs results in a stress concentration, causing the elastic driving force to exceed the threshold value and driving the propagation of the disconnection along the interface. The model is applied to study the propagation/annihilation of single disconnection pairs, the relaxation of a perturbed interface, and shear coupling at various temperatures. The results are consistent with the current understanding of disconnections, and capture the effect of thermal softening.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1016/j.actamat.2021.117149DOIArticle
https://arxiv.org/abs/2106.03708arXivDiscussion Paper
ORCID:
AuthorORCID
Gokuli, Mahi0000-0001-9771-826X
Runnels, Brandon0000-0003-3043-5227
Additional Information:© 2021 Acta Materialia Inc. Published by Elsevier. Received 4 June 2021, Revised 28 June 2021, Accepted 29 June 2021, Available online 21 July 2021. The authors gratefully acknowledge Lawrence Berkeley National Laboratory (LBL) subcontract #7473053, which supported the development of the computational methods used in this work. In addition, MG acknowledges support from the California Institute of Technology Summer Undergraduate Research Fellowship (SURF) for Summer 2019 and Summer 2020. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Funders:
Funding AgencyGrant Number
Lawrence Berkeley National Laboratory7473053
Caltech Summer Undergraduate Research Fellowship (SURF)UNSPECIFIED
DOI:10.1016/j.actamat.2021.117149
Record Number:CaltechAUTHORS:20210908-225044611
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20210908-225044611
Official Citation:Mahi Gokuli, Brandon Runnels, Multiphase field modeling of grain boundary migration mediated by emergent disconnections, Acta Materialia, Volume 217, 2021, 117149, ISSN 1359-6454, https://doi.org/10.1016/j.actamat.2021.117149.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:110791
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:09 Sep 2021 15:39
Last Modified:09 Sep 2021 15:39

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