Dipole drift mechanism of early stages of dislocation pattern formation in deformed metal single crystals

Kratochvı́l, Jan; Libovický, S.

doi:10.1016/0036-9748(86)90408-4

Cited by 63 publications

(19 citation statements)

References 14 publications

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“…Other plastic properties of crystalline materials are also closely related to the dislocation patterning and dynamic properties of dislocation motion. To better understand, to model these properties, and to describe these self-organized structures and dislocation patterns observed by transmission electron microscopy during the past decades, several analytical and computational methods have been developed, [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] but we are still far from a complete understanding of these phenomena.…”

Section: Introductionmentioning

confidence: 99%

Cellular dislocation patterning during plastic deformation

Bakó

Hoffelner

2007

Phys. Rev. B

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A simulation of dislocation patterning in a two-dimensional multislip configuration is carried out by means of coarse graining in the presence of plastic strain. In order to study the influence of climb on the dislocation cell pattern formation, fatigue simulations with and without climb mobility are performed and compared. The main result is that, in the presence of climb, cellular structures with well-defined characteristic length emerge, in contrast to the self-similar dislocation patterns developing under similar deformation conditions in the absence of climb. Despite the simplicity of our model, the fractal dimension of the self-similar dislocation patterns emerging without climb confirms the previous results for fcc crystals deformed in a multislip configuration. The cell structures emerging when climb is not negligible ͑in our simulations a climb mobility 1000 times smaller than the glide mobility was considered͒ resemble the dislocation patterns seen in thermal recovery or melt-grown experiments.

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Section: Introductionmentioning

confidence: 99%

Cellular dislocation patterning during plastic deformation

Bakó

Hoffelner

2007

Phys. Rev. B

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“…As an another example, micrographs show that dislocation patterns formed during a single slip in tension and cycling tend to have the same geometry and size; however, the tensile patterns are less ordered. 26 Anyway, we indicate below some possibilities for the specification and evaluation of the constitutive functionals.…”

Section: Specification Of the Constitutive Functionalsmentioning

confidence: 99%

Statistical foundation of continuum dislocation plasticity

Kratochvı́l

Sedláček

2008

Phys. Rev. B

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A continuum model of mesoscale plasticity intended to cover dislocation pattering and size effects is proposed. The statistical approach to dislocation dynamics put forward by Groma et al. ͓Acta Mater. 51, 1271 ͑2003͔͒ is applied to curved glide dislocations and dipolar dislocation loops appearing in a crystal deformed by single slip. Due to the very different size and mobile properties of the glide dislocations and the loops, the two entities are differently treated. The statistics of Groma et al. is directly applicable to the loops, which behave as rigid objects of restricted mobility. The glide dislocations are divided into groups, which in the averaging process lead to so-called single-valued dislocation fields. The averaged continuous distribution of the glide dislocations is treated as a superposition of these fields. The system of equations of the continuum model consists of ͑i͒ equations for the flow of glide dislocations of each single-valued field and the balance equation for the density of dipolar loops ͑these equations are derived from the discrete equations of motion and contain constitutive functionals representing short range interactions͒, ͑ii͒ the conservation of Burgers vector in the single-valued fields, ͑iii͒ the equations of continuum crystal plasticity, and ͑iv͒ the Orowan law for the shear strain rate caused by the glide dislocations. The possibilities for specification and evaluation of the constitutive functionals, namely, the short range correlations among dislocations ͑both the glide dislocations and the loops͒, are indicated.

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“…At the same time, other researchers have contributed substantially to the gradient approach: Coleman and co-workers [10,11] on mathematical aspects of the theory in relation to necking and shear banding; Kubin and co-workers [12,13] on the physical origin of the gradient terms for both dislocation and strain localization problems; Kratochvil and co-workers [14,15] on formulation aspects in relation to dislocation patterning; Hähner and co-workers [16,17] on microscopic and probabilistic aspects; and, finally, de Borst and co-workers [18,19], Belytschko and co-workers [20,21] and Tomita and co-workers [22] made significant contributions with emphasis on numerical aspects of the theory and its implementation to finite element codes. In parallel, other approaches (commonly referred to as non local damage theories [23]) have appeared in the literature as an outgrowth of earlier works by Eringen [24,25], and recent works by Bazant and co-workers [26][27][28][29].…”

Section: Background and State Of The Artmentioning

confidence: 99%