Interaction of Dislocations with an Applied Stress in Anisotropic Crystals

deWit, G.; Koehler, J. S.

doi:10.1103/physrev.116.1113

Cited by 292 publications

(87 citation statements)

References 9 publications

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“…Since the uniform line tension model predicts the symmetric form (an arc), we have to incorporate an orientation dependent line tension in order to explain the asymmetric dislocation shape. Indeed, de Wit and Koehler [18] obtained a solution for the dislocation shape. (7) and (8), which are derived from an orientation dependent line tension model.…”

Section: The Dislocation Shape and The Critical Anglementioning

confidence: 99%

Molecular dynamics investigation of dislocation pinning by a nanovoid in copper

Hatano

Matsui

2005

Phys. Rev. B

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Interactions between an edge dislocation and a void in copper are investigated by means of molecular dynamics simulation. The depinning stresses of the leading partial and of the trailing partial show qualitatively different behaviors. The depinning stress of the trailing partial increases logarithmically with the void radius, while that of the leading partial shows a crossover at 1 nm above which two partials are simultaneously trapped by the void. The pinning angle, which characterizes the obstacle strength, approaches zero when the void radius exceeds 3 nm. No temperature dependence is found in the critical stress and the critical angle. This is attributed to an absence of climb motion. The distance between the void center and a glide plane asymmetrically affects the pinning strength.

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Section: The Dislocation Shape and The Critical Anglementioning

confidence: 99%

Molecular dynamics investigation of dislocation pinning by a nanovoid in copper

Hatano

Matsui

2005

Phys. Rev. B

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“…Central to many of these models is the concept of the dislocation line tension Γ, which is associated with the energy required to form curved dislocation structures. Formally, the line tension is related to the infinitesimal change in energy δW associated with an infinitesimal change in dislocation length δS [22][23][24][25] …”

Section: Introductionmentioning

confidence: 99%

Robust atomistic calculation of dislocation line tension

Szajewski¹,

Pavia²

2015

Modelling Simul. Mater. Sci. Eng.

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Abstract. The line tension Γ of a dislocation is an important and fundamental property ubiquitous to continuum scale models of metal plasticity. However, the precise value of Γ in a given material has proven difficult to assess, with literature values encompassing a wide range. Here results from a multiscale simulation and robust analysis of the dislocation line tension, for dislocation bow-out between pinning points, are presented for two widely-used interatomic potentials for Al. A central part of the analysis involves an effective Peierls stress applicable to curved dislocation structures that markedly differs from that of perfectly straight dislocations but is required to describe the bow-out both in loading and unloading. The line tensions for the two interatomic potentials are similar and provide robust numerical values for Al. Most importantly, the atomic results show notable differences with singular anisotropic elastic dislocation theory in that (i) the coefficient of the ln(L) scaling with dislocation length L differs and (ii) the ratio of screw to edge line tension is smaller than predicted by anisotropic elasticity. These differences are attributed to local dislocation core interactions that remain beyond the scope of elasticity theory. The many differing literature values for Γ are attributed to various approximations and inaccuracies in previous approaches. The results here indicate that continuum line dislocation models, based on elasticity theory and various core-cut-off assumptions, may be fundamentally unable to reproduce full atomistic results, thus hampering the detailed predictive ability of such continuum models.

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“…Equating I to the mean square obstacle spacing in these units, Is/b, in equations (2) and (4) where K is 1 for edge dislocations and (1 -v) for screw dislocations. It should be noted that this equation for the line tension differs from the standard form derived by deWit and Koehler (1959). The identification of variables within the logarithmic term is somewhat arbitrary.…”

Section: N2 the Effect Of Dislocation Self-interactionsmentioning

confidence: 82%