Crystal plasticity modeling and simulation considering the behavior of the dislocation source of ultrafine-grained metal

Aoyagi, Yoshiteru; Tsuru, Tomohito; Shimokawa, Tomotsugu

doi:10.1016/j.ijplas.2013.09.009

Cited by 54 publications

(15 citation statements)

References 31 publications

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“…Sauvage et al [17] showed that GBs in UFG metals differ from regular GBs by atomic structure and stress fields. Stressstrain responses such as increased yield stress and yield point drop were analyzed for UFG FCC polycrystal from the viewpoint of grain size and dislocation density in FE simulations [18].…”

Section: Introductionmentioning

confidence: 99%

Hardening by Annealing and Implementation of High Ductility of Ultra-Fine Grained Aluminum: Experiment and Theory

Orlova

Скиба

Mavlyutov

et al. 2018

Reviews on Advanced Materials Science

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The influence of low temperature annealing and subsequent deformation on microstructure, strength and ductility was investigated for the first time for high pressure torsion (HPT) processed commercially pure Al. Extremely high increases in the conventional yield stress (up to 50%) and ultimate tensile strength (up to 30%) were obtained by annealing of the ultrafine grained (UFG) samples in the range 90-200 °C for 1 h. Such increases were accompanied by a sharp drop in ductility up to 1%. Implementation of high ductility at the level of coarse-grained Al, while maintaining high strength of the HPT-processed sample was demonstrated for the first time and achieved by repeating the low temperature annealing followed by subsequent additional HPT deformation. The key role of relaxation of non-equilibrium high-angle grain boundaries (GBs) in the strengthening effect of UFG-Al by annealing is shown. Two theoretical models are suggested to explain the hardening by annealing and the implementation of high ductility in UFG structures. Within the models, plastic deformation occurs through emission of lattice dislocations from triple junctions of GBs containing pile-ups of grain-boundary dislocations, glide of the lattice dislocations across neighboring grains, their accumulation at and climb along the opposite GBs. The energy characteristics and the critical stresses of dislocation emission are determined in two different cases, for UFG Al subjected to annealing only and to annealing with subsequent additional HPT deformation. The calculated theoretical dependences of the flow stress on the plastic deformation value well fit qualitatively and quantitatively to our experimental data.

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Section: Introductionmentioning

confidence: 99%

Hardening by Annealing and Implementation of High Ductility of Ultra-Fine Grained Aluminum: Experiment and Theory

Orlova

Скиба

Mavlyutov

et al. 2018

Reviews on Advanced Materials Science

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“…The formation of these spurious oscillations is known as the Gibbs phenomenon. In the context of present work, this phenomenon would be incurred in computing the strains (Cauchy stress) and curvatures (couple stress) using equations (34) and (35), respectively, due to discontinuous initial curvatures and inhomogeneous elastic constants C at the interface.…”

Section: Gibbs Phenomenon and Its Discrete Fourier Transform Based Numentioning

confidence: 99%

“…curvatures. While the role of strain gradients on plasticity in nc materials [29][30][31][32][33][34][35][36][37] has received considerable interest over the past decade, the role of rotational gradients i.e. lattice curvatures has received disproportionately less attention.…”

Section: Introductionmentioning

confidence: 99%

A higher order elasto-viscoplastic model using fast Fourier transforms: Effects of lattice curvatures on mechanical response of nanocrystalline metals

Upadhyay

Capolungo

Taupin

et al. 2016

International Journal of Plasticity

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In this work a couple stress continuum based elasto-viscoplastic fast Fourier transform model is developed with the intent to study the role of curvatures-gradient of rotation-on the local meso scale and effective macroscale mechanical response of nanocrystalline materials. Development of this model has led to the formulation of an extended periodic Lippmann Schwinger equation that accounts for couple stress equilibrium. In addition to the standard boundary conditions on strain rate and Cauchy stresses, the model allows imposing non-standard couple stress and curvature rate boundary conditions. Application to representative nanocrystalline microstructures reveals that elastic and plastic curvatures accommodate a part of the local and macroscopic Cauchy stresses. Next, grain boundary interfaces are characterized using curvatures that are representative of their structure and defect content. Depending on the magnitude and distribution of these curvatures, local stresses in the grain boundary neighborhood are generated that activate slip systems besides those fulfilling the Schmid criterion. Generation of both polar dislocations and disclinations as a possible plasticity mechanism

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“…Naturally, we can do no more than mention a few experimental and theoretical studies related to dislocation physics and solids mechanics, e.g. [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. We have recently made a significant discovery that the deforming medium is a self-organizing system, which is in a state far from thermodynamic equilibrium; such media are addressed by [15][16][17][18][19][20][21][22][23][24].…”

Section: Introduction General Considerationmentioning

confidence: 99%

Autowave Mechanics of Plastic Flow

Зуев

2020

Springer Tracts in Mechanical Engineering

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The notions of plastic flow localization are reviewed here. It have been shown that each type of localized plasticity pattern corresponds to a given stage of deformation hardening. In the course of plastic flow development a changeover in the types of localization patterns occurs. The types of localization patterns are limited to a total of four pattern types. A correspondence has been set up between the emergent localization pattern and the respective flow stage. It is found that the localization patterns are manifestations of the autowave nature of plastic flow localization process, with each pattern type corresponding to a definite type of autowave. Propagation velocity, dispersion and grain size dependence of wavelength have been determined experimentally for the phase autowave. An elastic-plastic strain invariant has also been introduced to relate the elastic and plastic properties of the deforming medium. It is found that the autowave’s characteristics follow directly from the latter invariant. A hypothetic quasi-particle has been introduced which correlates with the localized plasticity autowave; the probable properties of the quasi-particle have been estimated. Taking the quasi-particle approach, the characteristics of the plastic flow localization process are considered herein.

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Crystal plasticity modeling and simulation considering the behavior of the dislocation source of ultrafine-grained metal

Cited by 54 publications

References 31 publications

Hardening by Annealing and Implementation of High Ductility of Ultra-Fine Grained Aluminum: Experiment and Theory

Hardening by Annealing and Implementation of High Ductility of Ultra-Fine Grained Aluminum: Experiment and Theory

A higher order elasto-viscoplastic model using fast Fourier transforms: Effects of lattice curvatures on mechanical response of nanocrystalline metals

Autowave Mechanics of Plastic Flow

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