Optimal transportation of grain boundaries: A forward model for predicting migration mechanisms

Chesser, Ian; Holm, Elizabeth A.; Runnels, Brandon

doi:10.1016/j.actamat.2021.116823

Cited by 13 publications

(17 citation statements)

References 59 publications

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“…It has been observed in molecular dynamics simulations that both the simulation domain size and the temperature substantially affect the shear coupling behavior. This may be the result of a number of possible thermally activated mechanisms, including the activation of alternate disconnection modes (and corresponding shuffle patterns) [74]. Since disconnection nucleation is a thermally activated mechanism, it is also a mechanism by which temperature can affect migration propensity.…”

Section: Thermally-activated Shear Couplingmentioning

confidence: 99%

Multiphase field modeling of grain boundary migration mediated by emergent disconnections

Gokuli

Runnels

2021

Acta Materialia

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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.

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Section: Thermally-activated Shear Couplingmentioning

confidence: 99%

Multiphase field modeling of grain boundary migration mediated by emergent disconnections

Gokuli

Runnels

2021

Acta Materialia

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“…u 0 defines a plane about which no deformation is subtracted. Disconnection step height h may be inferred from the periodicity of the SDP with respect to choice of u 0 , as depicted in [37]. Note that the SDP representation is a superset of other types of representations.…”

Section: The Shear Shuffle Decompositionmentioning

confidence: 99%

“…At high temperatures, widening distributions in length and orientation often make tabulation of unique shuffling vectors difficult. Robust segmentation of displacement data from MD simulations was one motivation for the development of the forward model in [37].…”

Section: Displacement Pole Figures: Implementation and Conventionsmentioning

confidence: 99%

“…We refer to the shuffle minimizing transformation as the min-shuffle transformation. In a companion paper to this work, the min-shuffle transformation was predicted in an optimal transport framework [37]. Regularization in the optimal transport based forward model allowed for identification of longer, non-optimal displacements.…”

Section: The Min-shuffle Decompositionmentioning

confidence: 99%

“…In order to construct a taxonomy of GB migration mechanisms via displacement texture analysis, we consider a diverse set of migration scenarios including the motion of twin boundaries, disconnection mediated shear coupled motion, and constrained mixed mechanism scenarios involving shuffling, sliding and GB self diffusion. In combination with displacement texture characterization, a main analysis method of this work is a recently introduced forward model for GB migration which enables the interpretation of noisy and multimodal displacement data [37]. The main idea of the forward model is to generate a large catalog of GB migration mechanisms to compare to MD data.…”

Section: Introductionmentioning

confidence: 99%

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A taxonomy of grain boundary migration mechanisms via displacement texture characterization

Chesser,

Runnels,

Holm

2021

Preprint

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Atomistic simulations provide the most detailed picture of grain boundary (GB) migration currently available. Nevertheless, extracting unit mechanisms from atomistic simulation data is difficult because of the zoo of competing, geometrically complex 3D atomic rearrangement processes. In this work, we introduce the displacement texture characterization framework for analyzing atomic rearrangement events during GB migration, combining ideas from slip vector analysis, bicrystallography and optimal transportation. Two types of decompositions of displacement data are described: the shear-shuffle and min-shuffle decomposition.The former is used to extract shuffling patterns from shear coupled migration trajectories and the latter is used to separate geometrically distinct, temperature dependent shuffling mechanisms. As an application of the displacement texture framework, we characterize the GB geometry dependence of shuffling mechanisms for a crystallographically diverse set of mobile GBs in FCC Ni bicrystals. Two scientific contributions from this analysis include 1) an explanation of the boundary plane dependence of shuffling patterns via metastable GB geometry and 2) a taxonomy of multimodal constrained GB migration mechanisms which may include multiple competing shuffling patterns, period doubling effects, distinct sliding and shear coupling events, and GB self diffusion.

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Relation Between Parameters of Indirect Texture Control and Properties of Brass and Improvement of the Quality of Rolled Products by Using Statistical Methods of Analysis and Advanced Online Management

Pevzner

2024

Met Sci Heat Treat

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Optimal transportation of grain boundaries: A forward model for predicting migration mechanisms

Cited by 13 publications

References 59 publications

Multiphase field modeling of grain boundary migration mediated by emergent disconnections

Multiphase field modeling of grain boundary migration mediated by emergent disconnections

A taxonomy of grain boundary migration mechanisms via displacement texture characterization

Relation Between Parameters of Indirect Texture Control and Properties of Brass and Improvement of the Quality of Rolled Products by Using Statistical Methods of Analysis and Advanced Online Management

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