Analysis of single crystalline microwires under torsion using a dislocation-based continuum formulation

Zoller, Kolja; Schulz, Katrin

doi:10.1016/j.actamat.2020.03.057

Cited by 12 publications

(18 citation statements)

References 44 publications

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“…We take into account multiplication processes including glissile reaction and cross-slip according to [44] as well as interaction due to Lomer and collinear reactions. This is complemented by the homogenized dislocation source model introduced in [46]. Although several parts of the CDD formulation are known from the literature mentioned above, the used formulation including the considered stress interaction terms, dislocation reactions and the mobility law is presented in this subsection for a better readability.…”

Section: Dislocation Density Based Continuum Modelmentioning

confidence: 99%

“…This may result in dislocation multiplication as well as increase, transfer or decrease of dislocations line length within the system. The homogenized, mechanism based dislocation source model according to [46] considers the production of new dislocations loops. Dislocation sources on the individual slip systems can be activated locally if the effective stress on the individual slip system exceeds the respective critical source stress that depends on the current microstructure.…”

Section: Dislocation Density Based Continuum Modelmentioning

confidence: 99%

“…The comparison of the results with DDD simulations showed that the proposed scheme yields a physically correct representation of the interplay between dislocation densities on different slip systems. As such, the 3d CDD model has become capable of being successfully applied to realistic deformation problems, like torsion of microwires [46].…”

Section: Introductionmentioning

confidence: 99%

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Microstructure evolution of compressed micropillars investigated by in situ HR-EBSD analysis and dislocation density simulations

Zoller¹,

Kalácska²,

Ispánovity³

et al. 2021

Comptes Rendus. Physique

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Section: Dislocation Density Based Continuum Modelmentioning

confidence: 99%

Section: Dislocation Density Based Continuum Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Microstructure evolution of compressed micropillars investigated by in situ HR-EBSD analysis and dislocation density simulations

Zoller¹,

Kalácska²,

Ispánovity³

et al. 2021

Comptes Rendus. Physique

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“…This is inconsistent with the findings of most existing studies of macroscopic OFHC copper under dynamic loading, and there is uncertainty in strain rate sensitivity at macro-scale [24,30,31]. Zoller et al [32] found that when the geometrical size was reduced, an increase in strain gradient led to an increase in dislocation density. According to Orowan's relationship, strain rate and stress are influenced by dislocation velocity and dislocation density [33,34].…”

Section: Shpb Experimentsmentioning

confidence: 81%

Influence of Size Effect on Dynamic Mechanical Properties of OFHC Copper at Micro/Mesoscopic Scale

Jing

Wang

Zhang

et al. 2021

Preprint

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The dynamic mechanical properties of metallic materials have been extensively investigated at the macro-scale in terms of deformation mechanisms, strain rate strengthening, and fracture mechanisms. However, the dynamic mechanical properties affected by size effects at micro/meso-scales have rarely been investigated. To explore the size effects on the dynamic mechanical properties at micro/meso-scales, the experiments of quasi-static compression and SHPB were carried out using oxygen-free, high-conductivity (OFHC) copper with different geometrical and grain sizes. The experimental results show that the quasi-static and dynamic mechanical properties of OFHC copper are affected by size effects at micro/meso-scales. In particular, OFHC copper exhibits strain rate strengthening effects at the micro/meso-scales, and the presence of micro-cracks was observed in the SHPB experimental specimens. The J-C constitutive model based on the surface layer model is proposed and the analysis of the average relative error of the modified model and the original constitutive model is performed. Finite element analysis was carried out based on the modified J-C model and the original model, and the results show that the modified J-C model was in good agreement with the experimental results.

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“…In this section we derived kinematic evolution Eqs. (49,48) for the density fields ρ and q defined on the 2+1D space. Together with the velocity field v (r, ϕ) they form a closed set of kinematic evolution equations.…”

Section: Kinematics Of Curved Dislocationsmentioning

confidence: 99%

Dynamics of curved dislocation ensembles

2021

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To develop a dislocation-based statistical continuum theory of crystal plasticity is a major challenge of materials science. During the last two decades such a theory has been developed for the time evolution of a system of parallel edge dislocations. The evolution equations were derived by a systematic coarse-graining of the equations of motion of the individual dislocations and later retrieved from a functional of the dislocation densities and the stress potential by applying the standard formalism of phase field theories. It is, however, a long standing issue if a similar procedure can be established for curved dislocation systems. An important prerequisite for such a theory has recently been established through a density-based kinematic theory of moving curves. In this paper, an approach is presented for a systematic derivation of the dynamics of systems of curved dislocations in a single slip situation. In order to reduce the complexity of the problem a "dipole" like approximation for the orientation dependent density variables is applied. This leads to a closed set of kinematic evolution equations of total dislocation density, the GND densities, and the so-called curvature density. The analogy of the resulting equations with the edge dislocation model allows one to generalize the phase field formalism and to obtain a closed set of dynamic evolution equations.

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Analysis of single crystalline microwires under torsion using a dislocation-based continuum formulation

Cited by 12 publications

References 44 publications

Microstructure evolution of compressed micropillars investigated by in situ HR-EBSD analysis and dislocation density simulations

Microstructure evolution of compressed micropillars investigated by in situ HR-EBSD analysis and dislocation density simulations

Influence of Size Effect on Dynamic Mechanical Properties of OFHC Copper at Micro/Mesoscopic Scale

Dynamics of curved dislocation ensembles

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