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dislocation impediment by the grain boundaries in

dislocation impediment by the grain boundaries in

dislocation impediment by the grain boundaries in

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Dislocation impediment by the grain boundaries in polycrystalsAug 20, 2020 · Abstract: Thermodynamic dislocation theory incorporating dislocation impediment by the grain boundaries is developed to analyze the shear test of polycrystals. With a small set of physics based material parameters, we are able to simulate the stress-strain curves for the load and its reversal, which are consistent with the experimental curves of Thuillier and Manach [2009].Author: Yinguang Piao, Khanh Chau LePublish Year: 2020

What is the difference between grain boundaries and dislocation impediment by the grain boundaries in

Grain boundaries, on the other hand, are areas where the growing crystal lattice stopped or met another growing crystal lattice. Here is where my confusion begins. To me a grain boundary would be similar to a dislocation. It is an imperfect part of the crystal pattern. This imperfection would put strains on the bonds just like a dislocation.Topological Defects in Graphene: Dislocations and Grain dislocation impediment by the grain boundaries inGrain boundary energies per dislocation D as a function of inverse distance D between the neighboring dislocations. Dashed line shows the least-squares fit. Figures - uploaded by Oleg V. YazyevStress Localization Resulting from Grain Boundary dislocation impediment by the grain boundaries inNov 13, 2019 · The development of the localized stress and strain regions is studied as dislocations are emitted from and arrive at grain boundaries. Digital samples with two different degrees of disorder in the grain boundaries but otherwise identical microstructures are compared in order to understand the effects of additional defects on the stress concentration that develops at the grain boundaries.

Phonon scattering by dislocations at grain boundaries in dislocation impediment by the grain boundaries in

In addition to the boundary scattering, we have recently demonstrated that dense arrays of dislocations formed in grain boundaries can further reduce the l by dislocation scattering at Cited by: 20Publish Year: 2017Author: Hyun Sik Kim, Hyun Sik Kim, Hyun Sik Kim, Sang Il Kim, Kyu Hyoung Lee, Sung Wng Kim, G. Jeffrey Snyd dislocation impediment by the grain boundaries inOn the absorption of dislocations by grain boundaries: The dislocation impediment by the grain boundaries inOct 24, 2006 · Abstract. Abstract. A lattice dislocation may lower its elastic energy by dissociation in a high angle grain boundary. The absorption process involves the separation of the product grain boundary dislocations at a rate limited in general by climb and their interaction with any pre-existing network. This description of the absorption process is extended to random boundaries with the help of Observation of misfit dislocation arrays in high angle dislocation impediment by the grain boundaries inAug 20, 2006 · A considerable number of boundaries was prepared by welding epitaxial thin films of gold together at various twist angles. Orthogonal arrays of grain boundary misfit dislocations were detected in the vicinity of the critical angles at which the two highest density coincidence site interfaces are formed in this system.

Observation of hydrogen trapping at dislocations, grain dislocation impediment by the grain boundaries in

Jan 10, 2020 · Direct observation of hydrogen at carbon-rich dislocations and grain boundaries provides validation for embrittlement models. Hydrogen observed at Grainboundary,crystallinedefects(includingdislocation dislocation impediment by the grain boundaries inA Grain Boundary is a general planar defect that separates regions of different crystalline orientation (i.e. grains) within a polycrystalline solid. The atoms in the grain boundary will not be in perfect crystalline arrangement. Grain boundaries are usually the result of uneven growth when the solid is crystallising. Grain sizes vary from 1 µm to 1 mm.Grain-Boundary Dislocation Climb and Diffusion in dislocation impediment by the grain boundaries inplacements of grain-boundary dislocations are accom-panied by changes in their dilatation elds, which e xert a noticeable effect on the migration of point defects, i.e., diffusion carriers, while the dislocation climb in grain boundaries is accompanied by the emission and absorption of

Grain Boundaries and Dislocations | Science

Apr 05, 2002 · Dislocations can move through the crystal grains and can interact with each other (1). Grain boundaries often hinder their transmission, creating a dislocation pile-up at Cited by: 767Publish Year: 2002Author: Helena Van SwygenhovenEffects of solutes on dislocation nucleation from grain dislocation impediment by the grain boundaries inWhen grain sizes are reduced to the nanoscale, grain boundaries (GB) become the dominant sources of the dislocations that enable plastic deformation. Here, we present the first molecular dynamics (MD) study of the effect of substitutional solutes on the dislocation nucleation process from GBs during uniaxial tensile deformation.Dislocations, Disclinations, and Grain Boundaries in a dislocation impediment by the grain boundaries inAn earlier surface dislocation analysis applied to infinite grain boundaries is extended to grain boundaries and disclinations in a finite solid. The coalescence of the grain boundary surfaces is described by grain boundary surface dislocation arrays. The conservation of Burgers vectors is satisfied by the screening dislocation array.Cited by: 6Publish Year: 1979Author: K. Jagannadham, M. J. Marcinkowski

Dislocations in Grain Boundary Regions: The Origin of dislocation impediment by the grain boundaries in

Nov 06, 2019 · Dislocation activity in nanocrystalline materials has been widely investigated by molecular dynamic (MD) simulations.[2,3,4,7,8,9,10,14] In many cases, MD simulations predict that grain boundaries (GBs) emit partial dislocations pulling stacking faults or twin boundaries decorating grain interiors at the end of straining.[2,3,8,10,12] Line profile analysis of X-ray diffraction patterns reveals Cited by: 5Publish Year: 2020Author: Zhenbo Zhang, Éva Ódor, Diana Farkas, Bertalan Jóni, Gábor Ribárik, Géza Tichy, Sree-Harsha Nandam, dislocation impediment by the grain boundaries inDislocations and Grain Boundaries in Two-Dimensional Dislocations and Grain Boundaries in Two-Dimensional Boron Nitride | ACS Nano. A new dislocation structuresquare-octagon pair (4|8) is discovered in two-dimensional boron nitride (h-BN), via first-principles calculations. It has lower energy than corresponding pentagonheptagon pairs (5|7), which contain unfavorable homoelemental bonds.Dislocation reactions, grain boundaries, and dislocation impediment by the grain boundaries inSep 24, 2013 · At the corners, fusion of dislocations from adjoining edges produces dislocations oriented in the clockwise pattern of a grain boundary. The linear density of dislocations (Fig. 4C) dictates the orientational mismatch of the crystal on crossing the grain boundary. The creation and rearrangement of the dislocations lowers the elastic energy.Cited by: 61Publish Year: 2013Author: William T. M. Irvine, Andrew D. Hollingsworth, David G. Grier, Paul M. Chaikin

Dislocation nucleation from damaged grain boundaries in dislocation impediment by the grain boundaries in

Dec 01, 2019 · It is found that macroscopic grain boundary descriptors fail to uniquely predict the strength of damaged grain boundaries, thus suggesting some other mechanistic rationale for the role of such boundaries in governing dislocation nucleation under uniaxial tension in metals.Dislocation nucleation from bicrystal interfaces and grain dislocation impediment by the grain boundaries inThe grain boundary dislocation emission mechanism was rst ARTICLE IN PRESS 2302 L. Capolungo et al. / J. Mech. Phys. Solids 55 (2007) 23002327. suggested by Li (1963) in order to describe the HallPetch relation. In this model, dislocations are emitted by grain boundary ledges which act as simple dislocation donorsDislocation impediment by the grain boundaries in polycrystalsAug 20, 2020 · Abstract: Thermodynamic dislocation theory incorporating dislocation impediment by the grain boundaries is developed to analyze the shear test of polycrystals. With a small set of physics based material parameters, we are able to simulate the stress-strain curves for the load and its reversal, which are consistent with the experimental curves of Thuillier and Manach [2009].Author: Yinguang Piao, Khanh Chau LePublish Year: 2020

Dislocation emission from deformation-distorted grain dislocation impediment by the grain boundaries in

Apr 01, 2014 · Emission of lattice dislocations from grain boundaries (GBs) specified by deformation-distorted structures with periodic fluctuations of misorientation in deformed ultrafine-grained (UFG) materials is theoretically described. It is theoretically revealed that (i) the dislocation emission from deformation-distorted GBs is significantly enhanced as compared to that from structurally equilibrated GBs; and (ii) the enhancement effect depends on the parameters specifying the deformation-distorted dislocation impediment by the grain boundaries inDirect observation of individual dislocation interaction dislocation impediment by the grain boundaries inNov 11, 2016 · The lattice dislocation impediment by grain boundaries does not simply originate from the geometric effects; it also arises as a result of local structural stabilization effects at their cores, especially in low-angle grain boundaries. The present findings indicate that both the geometric effects and the stabilization effects must be dislocation impediment by the grain boundaries inDirect observation of individual dislocation interaction dislocation impediment by the grain boundaries inNov 01, 2016 · The lattice dislocation impediment by grain boundaries does not simply originate from the geometric effects; it also arises as a result of local structural stabilization effects at their cores, dislocation impediment by the grain boundaries inCited by: 62Publish Year: 2016Author: Shun Kondo, Shun Kondo, Tasuku Mitsuma, Naoya Shibata, Naoya Shibata, Yuichi Ikuhara

Direct observation of individual dislocation interaction dislocation impediment by the grain boundaries in

grain boundaries, it is well accepted that grain boundary structures can be described by a periodic array of dislocations ( 29). In the present experiments, we fabricated an STO bicrystal including dislocation impediment by the grain boundaries inCited by: 62Publish Year: 2016Author: Shun Kondo, Shun Kondo, Tasuku Mitsuma, Naoya Shibata, Naoya Shibata, Yuichi IkuharaCritical assessment of hydrogen effects on the slip dislocation impediment by the grain boundaries inGrain boundaries (GBs) play a fundamental role in the strengthening mechanism of crystalline structures by acting as an impediment to dislocation motion. However, the presence of an aggressive environment such as hydrogen increases the susceptibility to intergranular fracture. Further, there is a lack of systematic investigations exploring the role of hydrogen on the dislocation-grain-boundary dislocation impediment by the grain boundaries inSome results are removed in response to a notice of local law requirement. For more information, please see here.Critical assessment of hydrogen effects on the slip dislocation impediment by the grain boundaries inGrain boundaries (GBs) play a fundamental role in the strengthening mechanism of crystalline structures by acting as an impediment to dislocation motion. However, the presence of an aggressive environment such as hydrogen increases the susceptibility to intergranular fracture. Further, there is a la Cited by: 14Publish Year: 2016Author: I. Adlakha, Kiran Solanki

Chapter 7: Dislocations and strengthening mechanisms

Grain growth Strengthening by grain size reduction Grain boundary acts as a barrier to dislocation motion Different crystallographic grains impede dislocation movement The atomic disorder within a grain boundary region will result in a discontinuity of slip plans Smaller size grains have more grain boundary than larger onesCHAPTER 7 DISLOCATIONS AND STRENGTHENING Grain boundaries are barriers to slip: Owing to misalignment of the slip planes in adjacent grains, a dislocation passing the grain boundary have to change its direction and thus lose its energy. A single grain may be favorably oriented for slip, but cannot deform until the adjacent grains (less favorable) are also capable to slip;

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