Results 251 to 260 of about 9,306 (283)
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Crystallographic aspects of geometrically-necessary and statistically-stored dislocation density
Acta Materialia, 1999Abstract Classical plasticity has reached its limit in describing crystalline material behavior at the micron level and below. Its inability to predict size-dependent effects at this length scale has motivated the use of higher-order gradients to model material behavior at the micron level.
A Arsenlis, D.M Parks
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Zeitschrift für angewandte Mathematik und Physik, 2020
The paper studies the geometric dislocation density tensor and Burgers vector using an elastic-plastic decomposition of Laplace stretch which arises from a QR decomposition of the deformation gradient and allows for direct experimental measurement. The geometric dislocation density tensor is obtained using the classical argument of failure of a Burgers
Sandipan Paul, Alan D. Freed
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The paper studies the geometric dislocation density tensor and Burgers vector using an elastic-plastic decomposition of Laplace stretch which arises from a QR decomposition of the deformation gradient and allows for direct experimental measurement. The geometric dislocation density tensor is obtained using the classical argument of failure of a Burgers
Sandipan Paul, Alan D. Freed
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Finite element analysis of geometrically necessary dislocations in crystal plasticity
International Journal for Numerical Methods in Engineering, 2012SUMMARYWe present a finite element method for the analysis of ductile crystals whose energy depends on the density of geometrically necessary dislocations (GNDs). We specifically focus on models in which the energy of the GNDs is assumed to be proportional to the total variation of the slip strains.
Hurtado, Daniel E., Ortiz, Michael
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Key Engineering Materials, 2016
As components with proportional feature and tooling sizes are miniaturized, strain gradients through the cross-section increase. This causes strain gradient hardening as the density of geometrically necessary dislocations increases. This will lead to higher required forces in the process than expected.
Li Jie Wang +2 more
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As components with proportional feature and tooling sizes are miniaturized, strain gradients through the cross-section increase. This causes strain gradient hardening as the density of geometrically necessary dislocations increases. This will lead to higher required forces in the process than expected.
Li Jie Wang +2 more
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Higher-Order Stress due to Self Energy of Geometrically Necessary Dislocations
Key Engineering Materials, 2007The self energy of geometrically necessary dislocations (GNDs) in single crystals is considered to inevitably introduce a higher-order stress as the work conjugate to slip gradient. It is pointed out that this higher-order stress changes stepwise in response to in-plane slip gradient and thus explicitly influences the initial yielding of polycrystals ...
Nobutada Ohno, Dai Okumura
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Geometrically necessary dislocation fingerprints of dislocation loop absorption at grain boundaries
Physical Review Materials, 2022Larissa M. Woryk +7 more
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Determining Burgers vectors and geometrically necessary dislocation densities from atomistic data
Modelling and Simulation in Materials Science and Engineering, 2010We describe a novel analysis method to quantify the Burgers vectors of dislocations in atomistic ensembles and to calculate densities of geometrically necessary and statistically stored dislocations. This is accomplished by combining geometrical methods to determine dislocation cores and the slip vector analysis, which yields the relative slip of the ...
Jun Hua, Alexander Hartmaier
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Experimentally determined content of a geometrically necessary dislocation boundary in copper
Acta Materialia, 2004Abstract Weak beam and stereo transmission electron microscopy (TEM) were used to analyze the dislocation content of a crystallographic geometrically necessary dislocation boundary (GNB) in rolled copper. The GNB is oriented close to the ( 1 1 1) slip plane and is composed primarily of dislocations from the three highest stressed slip ...
Rodney J McCabe +2 more
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Identification of geometrically necessary dislocations in solid phase crystallized poly-Si
Journal of Applied Physics, 2013In this work, the presence of geometrically necessary dislocations (GNDs) in polycrystalline silicon (poly-Si) thin films was detected, suggesting that plastic deformation occurs during the solid phase crystallization (SPC) process of amorphous silicon (a-Si:H).
Law, F. +5 more
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Geometrically necessary dislocations in FCC polycrystalline metallic materials on the mesoscale
Bulletin of the Russian Academy of Sciences: Physics, 2011The dislocation structure of deformed copper alloys doped with Mn and Al was determined by selected area diffraction (SAD), performed using a transmission electron microscope. The scalar dislocation density, the density of geometrically necessary dislocations, and the density of statistically stored dislocations were measured.
E. V. Kozlov +3 more
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