Standing wave effect and fractal structure in dislocation evolution

Li, P.; Zhang, Z. F.

doi:10.1038/s41598-017-04257-9

Cited by 9 publications

(6 citation statements)

References 35 publications

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“…Other defects such as stacking faults due to shear banding could also induce the observed phase patterns. [33,34] A trend toward more tensile strain with increasing deformation is readily observed in figure 4 where normalised histograms of the mean phase information are plotted for both the HIO (a -g) and reweighted 2D phase retrieval algorithms (h -n). Deformation increases from a to g and h to n. For the HIO algorithm, phase information histograms show no appreciable trend with increasing deformation.…”

Section: Resultsmentioning

confidence: 83%

Coherent diffraction imaging of a progressively deformed nanocrystal

Newton

Shi

Wagner

et al. 2019

Phys. Rev. Materials

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Imaging ordered materials with coherent x-rays holds great potential to improve our understanding of phenomena in complex materials systems where emergent behaviour can arise due to coupling of spin, lattice and orbital degrees of freedom. Coherent diffractive imaging (CDI) is a lensless imaging technique for probing the structure of materials in three-dimensions. Central to the success of the CDI method is the inversion of propagated wavefield information to recover a quantitative image of the illuminated crystalline structure. Present challenges faced with existing approaches to image recovery are often due to non-uniqueness of wave propagated forms of the electron density information that can cause prohibitive stagnation of the reconstruction algorithm. Here we report on a major advancement in image recovery that is able to recover the three-dimensional image of a 492 nm gold single crystal undergoing progressive deformation to a highly strained condition without the use of a priori information. Our findings also demonstrate the significance of robust image recovery techniques for revealing high resolution topological structure.

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Section: Resultsmentioning

confidence: 83%

Coherent diffraction imaging of a progressively deformed nanocrystal

Newton

Shi

Wagner

et al. 2019

Phys. Rev. Materials

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“…An excellent work done by Li et al 8 has systematically investigated dislocation patterns in face‐centered cubic (FCC) crystals under cyclic loading, in which the authors provided some experimental evidences for well‐defined and lattice‐like distribution dislocation microstructure. Later on, the same authors argued that these lattice‐like dislocation patterns are linked with the original crystal lattice with same standing wave effect and fractal structure 9 …”

Section: Introductionmentioning

confidence: 97%

Finite temperature atomistic‐informed crystal plasticity finite element modeling of single crystal tantalum (α‐Ta) at micron scale

Xie

2021

Numerical Meth Engineering

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In this work, we have developed a temperature‐dependent higher‐order Cauchy–Born (THCB) rule for multiscale crystal defect dynamics (MCDD) of crystalline solids based on the harmonic approximation. As a template, we employed the THCB rule to develop an atomistic‐informed constitutive model for the body‐centered cubic (BCC) single crystal tantalum (α‐Ta). Considering the effect of strain gradients in different process zone elements, the corresponding higher order stress are used to model crystal plasticity of single crystal α‐Ta. Different from face‐centered cubic crystals, BCC crystals are strongly influenced by temperature. It is shown in this article that the developed finite temperature atomistic‐informed crystal plasticity finite element method is able to capture the temperature‐dependent dislocation substructure and hence crystal plastic deformation. The main contributions and novelties of the present work are highlighted by following findings: (1) A THCB rule and an atomistic‐informed strain gradient theory have been developed, and the corresponding temperature‐related higher‐order stress and elastic tensor formulations are derived; (2) The finite temperature MCDD provides an atomistic‐informed crystal plasticity finite element method that can simulate anisotropic crystal plasticity in any orientation within stereographic triangle at micron scale and above; (3) The developed MCDD is able to capture the non‐Schmid effects of BCC single crystal tantalum (α‐Ta); (4) The developed MCDD is able to capture the size effect of single crystal plasticity; and (5) The finite temperature MCDD can simulate the temperature dependent dislocation substructure, and it captures cross‐slip in single crystal tantalum at low temperature (∼20 K) and captures dislocation cell structure at high temperature (∼500 K).

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“…This led to the establishment of an independent branch of optics called singular optics [32][33][34]. The study of phase singularities in optics [35][36][37] was born from an analogy between these singularities in complex fields and dislocations in crystals [38][39][40].…”

Section: Introductionmentioning

confidence: 99%

A method for the dynamics of vortices in a Bose-Einstein condensate: analytical equations of the trajectories of phase singularities

María-García¹,

Ferrando²,

A.³

et al. 2022

Preprint

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We present a method to study the dynamics of a quasi-two dimensional Bose-Einstein condensate which contains initially many vortices at arbitrary locations. We present first the analytical solution of the dynamics in a homogeneous medium and in a parabolic trap for the ideal non-interacting case. For the homogeneous case this was introduced in the context of photonics. Here we discuss this case in the context of Bose-Einstein condensates and extend the analytical solution to the trapped case, for the first time. This linear case allows one to obtain the trajectories of the position of phase singularities present in the initial condensate along with time. Also, it allows one to predict some quantities of interest, such as the time at which a vortex and an antivortex contained in the initial condensate will merge. Secondly, the method is complemented with numerical simulations of the non-linear case. We use a numerical split-step simulation of the non-linear Gross-Pitaevskii equation to determine how these trajectories and quantities of interest are changed by the presence of interactions. We illustrate the method with several simple cases of interest both in the homogeneous and parabolically trapped systems.

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Standing wave effect and fractal structure in dislocation evolution

Cited by 9 publications

References 35 publications

Coherent diffraction imaging of a progressively deformed nanocrystal

Coherent diffraction imaging of a progressively deformed nanocrystal

Finite temperature atomistic‐informed crystal plasticity finite element modeling of single crystal tantalum (α‐Ta) at micron scale

A method for the dynamics of vortices in a Bose-Einstein condensate: analytical equations of the trajectories of phase singularities

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