Geometrically necessary dislocation density
WebJun 1, 2024 · The so-called geometrically necessary dislocation (GND) density tensor was first described by Nye in 1953. Concepts of GND density and the dislocation … WebSep 27, 2024 · Abstract Wedge indentation experiments were conducted to study the depth dependence of geometrically necessary dislocation (GND) structures in single-crystalline tungsten. Single-crystalline tungsten exhibits a pronounced indentation size effect (ISE), which can be rationalized based on GNDs. The dislocation mechanisms, however, are …
Geometrically necessary dislocation density
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WebJul 9, 2015 · The effect of dislocation structure evolution on low-angle grain boundary formation in 7050 aluminum alloy during aging was studied by using optical microscopy, transmission electron microscopy, and electron backscatter diffraction analysis of misorientation angle distribution, cumulative misorientation and geometrically … WebJun 20, 2016 · Using EBSD, and based on the local average misorientation, it is possible to calculate the density of Geometrically Necessary Dislocations (GNDs). But there is a …
WebSep 1, 2012 · The lattice curvatures were used to form lower bound estimates of the geometrically necessary ... WebHigh-density geometrically necessary dislocation (GND) is retained in the alloy even after annealing at 800 °C for 3 h, as is the presence of parallel GND rows because they …
WebSemantic Scholar extracted view of "Geometrically necessary dislocation and size-dependent plasticity" by Huajian Gao et al. Skip to search form Skip to main content Skip to account menu ... A dislocation density based constitutive model has been developed and implemented into a crystal plasticity quasi‐static finite element framework. WebThe dislocation density 200 micrometres into the surface of a material has been shown to be six times higher than the density in the bulk. However, in polycrystalline materials the surface sources do not have a major effect because most grains are not in contact with the surface. ... Geometrically necessary dislocations
WebAug 17, 2024 · Arsenlis A, Parks D (1999) Crystallographic aspects of geometrically-necessary and statistically-stored dislocation density. Acta Mater 47(5):1597–1611. Article Google Scholar Kysar J, Saito Y, Oztop M, Lee D, Huh W (2010) Experimental lower bounds on geometrically necessary dislocation density. Int J Plast 26(8):1097–1123
WebJan 1, 2024 · Resolving geometrically necessary dislocation density onto individual dislocation types using EBSD-based continuum dislocation microscopy Journal Article Ruggles, T. J. ; Fullwood, D. T. ; Kysar, J. W. - International Journal of Plasticity establishing budget goalsWebAbstract. We report significant back stress strengthening and strain hardening in gradient structured (GS) interstitial-free (IF) steel. Back stress is long-range stress caused by the pileup of geometrically necessary dislocations (GNDs). A simple equation and a procedure are developed to calculate back stress basing on its formation physics ... firebaseservice flutterWebNov 4, 2024 · In Sect. 6, an evolution equation for the dislocation density tensor and a balance law for geometrically necessary dislocations are derived. Different types of dislocations are characterized using the newly obtained dislocation density tensor in Sect. 7 . firebase service statusThus the observation of geometrically necessary dislocations was realized using the curvature data. But due to experimental limitations, the density of geometrically necessary dislocation for a general deformation state was hard to measure until a lower bound method was introduced by Kysar et al. at 2010. See more Geometrically necessary dislocations are like-signed dislocations needed to accommodate for plastic bending in a crystalline material. They are present when a material's plastic deformation is accompanied by … See more Statistically stored dislocations As straining progresses, the dislocation density increases and the dislocation mobility decreases during plastic flow. There are different ways through which dislocations can accumulate. Many of the dislocations are … See more The uniaxial tensile test has largely been performed to obtain the stress-strain relations and related mechanical properties of bulk specimens. However, there is an extra storage of defects associated with non-uniform plastic deformation in … See more Single crystal The plastic bending of a single crystal can be used to illustrate the concept of geometrically necessary dislocation, where the slip … See more Nye has introduced a set of tensor (so-called Nye's tensor) to calculate the geometrically necessary dislocation density. For a three … See more Because $${\displaystyle \rho _{g}}$$ is in addition to the density of statistically stored dislocations $${\displaystyle \rho _{s}}$$, the increase in dislocation density due to accommodated polycrystals leads to a grain size effect during strain hardening; … See more firebase send notification to specific deviceWebUsing EBSD, and based on the local average misorientation, it is possible to calculate the density of Geometrically Necessary Dislocations (GNDs). But there is a huge debate on the accuracy of ... establishing business relationship letterWebOct 29, 2024 · A quasi-in-situ electron backscatter diffraction (EBSD) analysis reveals that at the same strain, the geometrically necessary dislocation (GND) density of the RT sample is the highest, followed by the GT sample and the PC sample. ... Gao et al. revealed that the density of geometrically necessary dislocations (GNDs) has a correlation with … establishing business relationshipsWebJan 13, 2003 · This theory is intended to link Taylor's model of dislocation hardening to a nonlocal theory of plasticity in which the density of geometrically necessary … establishing breastfeeding