Use of the Nye tensor in analyzing HREM images of bcc screw dislocations

Mendis, Budhika G.; Mishin, Y.; Hartley, Craig S.; Hemker, Kevin J.

doi:10.1080/14786430600660849

Cited by 47 publications

(34 citation statements)

References 25 publications

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“…The nonplanar core structure has been linked to the characteristic deformation behavior of the bcc transition metalse.g., large Peierls stress and significant deviations from the Schmid law. Since the possibility to observe the atomic structure of the core of screw dislocations directly is very limited, 123,124 it is an excellent topic for atomistic simulation and we present such a study using the constructed BOP's.…”

Section: Dislocationsmentioning

confidence: 99%

Bond-order potential for simulations of extended defects in tungsten

et al. 2007

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We present a bond-order potential (BOP) for the bcc transition metal tungsten. The bond-order potentials are a real-space semiempirical scheme for the description of interatomic interactions based on the tight-binding approximation. In the hierarchy of atomic-scale-modeling methods the BOPs thus provide a direct bridge between electronic-structure and atomistic techniques. Two variants of the BOP were constructed and extensively tested against accurate first-principles methods in order to assess the potentials' reliability and applicability. A comparison of the BOP with a central-force potential is used to demonstrate that a correct description of directional mixed covalent and metallic bonds is crucial for a successful and fully transferable model. The potentials are applied in studies of low-index surfaces, symmetrical tilt grain boundaries, and dislocations. We present a bond-order potential ͑BOP͒ for the bcc transition metal tungsten. The bond-order potentials are a real-space semiempirical scheme for the description of interatomic interactions based on the tight-binding approximation. In the hierarchy of atomic-scale-modeling methods the BOPs thus provide a direct bridge between electronic-structure and atomistic techniques. Two variants of the BOP were constructed and extensively tested against accurate first-principles methods in order to assess the potentials' reliability and applicability. A comparison of the BOP with a central-force potential is used to demonstrate that a correct description of directional mixed covalent and metallic bonds is crucial for a successful and fully transferable model. The potentials are applied in studies of low-index surfaces, symmetrical tilt grain boundaries, and dislocations.

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Section: Dislocationsmentioning

confidence: 99%

Bond-order potential for simulations of extended defects in tungsten

et al. 2007

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“…An important property of the Nye tensor is that it describes only the incompatible part of the elastic-plastic deformation field [23,32]. Therefore, any compatible distortion of the lattice for which the displacement field remains single-valued and the strain field integrable does not affect the Nye tensor.…”

Section: Determination Of the Anisotropic Eshelby Twistmentioning

confidence: 99%

Effect of Eshelby twist on core structure of screw dislocations in molybdenum: atomic structure and electron microscope image simulations

Gröger

Dudeck

Nellist

et al. 2011

Philosophical Magazine

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“…Each dislocation line is oriented parallel to 3 and is associated with a finite core. According to some high-resolution transmission electron microscopy observations and numerical simulations, for example, [23][24][25], a TD core can have a variety of atomic structures. These latter have certainly an influence on the elastic properties very near the theoretical dislocation line [25].…”

Section: The Fourier Calculation Approachmentioning

confidence: 99%

Threading Dislocations Piercing the Free Surface of an Anisotropic Hexagonal Crystal: Review of Theoretical Approaches

Neily

Dhouibi

Bonnet

2018

Advances in Condensed Matter Physics

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Inclined threading dislocations (TDs) piercing the oriented free surface of a crystal are currently observed after growth of oriented thin films on substrates. Up to date the unique way to treat their anisotropic elastic properties nearby the free surface region is to use the integral formalism, which assumes no dislocation core size and needs numerical double integrations. In a first stage of the work, a new and alternative approach to the integral formalism is developed using double Fourier series and the concept of a finite core size, which is often observed in high-resolution transmission electron microscopy. In a second stage, the integral formalism and the Fourier series approaches are applied to the important case of a TD piercing the basal free surface of a hexagonal crystal. For this particular geometry, easy-to-use expressions are derived and compared to a third approach previously known for a plate-like crystal. Finally, the numerical interest and the convergence of these approaches are tested using the basal free surface of the GaN compound, in particular for TDs with Burgers vectors c and (a + c).

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Use of the Nye tensor in analyzing HREM images of bcc screw dislocations

Cited by 47 publications

References 25 publications

Bond-order potential for simulations of extended defects in tungsten

Bond-order potential for simulations of extended defects in tungsten

Effect of Eshelby twist on core structure of screw dislocations in molybdenum: atomic structure and electron microscope image simulations

Threading Dislocations Piercing the Free Surface of an Anisotropic Hexagonal Crystal: Review of Theoretical Approaches

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