Nonplanar core structure of the screw dislocations in tantalum from the improved Peierls–Nabarro theory

Hu, Xiangsheng; Wang, Shaofeng

doi:10.1080/14786435.2017.1409442

Cited by 17 publications

(7 citation statements)

References 68 publications

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“…The continuous distribution of shear S(x) combined with the GSF energies yields the energy barrier for the glide of dislocation, which is used to calculate the Peierls stress. There have been large amounts of dislocation research based on the PN model [20][21][22][23][24][25][26][27][28][29][30][31] . The GSF calculations apply a rigid model to address atomic structure, in which the atoms are only allowed to relax along with the directions normal to shear direction [20][21][22][23][24][25][26][27][28][29][30][31] .…”

mentioning

confidence: 99%

“…There have been large amounts of dislocation research based on the PN model [20][21][22][23][24][25][26][27][28][29][30][31] . The GSF calculations apply a rigid model to address atomic structure, in which the atoms are only allowed to relax along with the directions normal to shear direction [20][21][22][23][24][25][26][27][28][29][30][31] . Accordingly, the GSF energy is purely inelastic strain energy.…”

mentioning

confidence: 99%

“…Accordingly, the GSF energy is purely inelastic strain energy. Although this approach has gained a great deal of success in metals and alloys [22][23][24][25][26][27][28][29] , it is still highly questionable to be applied to nonmetallic materials. The mixed feature of covalent and ionic bonding of non-metallic materials can bring some new challenges to correctly model the dislocation process.…”

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confidence: 99%

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Theoretical insights into the Peierls plasticity in SrTiO3 ceramics via dislocation remodelling

Zhang

et al. 2022

Nat Commun

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An in-depth understanding of the dislocations motion process in non-metallic materials becomes increasingly important, stimulated by the recent emergence of ceramics and semiconductors with unexpected room temperature dislocation-mediated plasticity. In this work, local misfit energy is put forward to accurately derive the Peierls stress and model the dislocation process in SrTiO3 ceramics instead of the generalized stacking fault (GSF) approach, which considers the in-plane freedom degrees of the atoms near the shear plane and describes the breaking and re-bonding processes of the complex chemical bonds. Particularly, we discover an abnormal shear-dependence of local misfit energy, which originates from the re-bonding process of the Ti-O bonds and the reversal of lattice dipoles. In addition, this approach predicts that oxygen vacancies in the SrTiO3 can facilitate the nucleation and activation of dislocations with improvement of fracture toughness, owing to the reduction of average misfit energy and Peierls stress due to the disappearance of lattice dipole reversal. This work provides undiscovered insights into the dislocation process in non-metallic materials, which may bring implications to tune the plasticity and explore unknown ductile compositions.

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confidence: 99%

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confidence: 99%

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Theoretical insights into the Peierls plasticity in SrTiO3 ceramics via dislocation remodelling

Zhang

et al. 2022

Nat Commun

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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%

“…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]. However, beyond a few |b| values and thanks to the St. Venant principle, elasticity can be applied without accounting for true limiting boundary conditions around the core.…”

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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Critical stress prediction upon accurate dislocation core description

2022

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Nonplanar core structure of the screw dislocations in tantalum from the improved Peierls–Nabarro theory

Cited by 17 publications

References 68 publications

Theoretical insights into the Peierls plasticity in SrTiO3 ceramics via dislocation remodelling

Theoretical insights into the Peierls plasticity in SrTiO3 ceramics via dislocation remodelling

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

Critical stress prediction upon accurate dislocation core description

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