Results 171 to 180 of about 304 (202)

A dislocation density based constitutive model for crystal plasticity FEM including geometrically necessary dislocations

Acta Materialia, 2006
A dislocation density based constitutive model for face-centred cubic crystals is introduced and implemented into a crystal plasticity finite element framework. The approach assumes a homogeneous dislocation structure and tracks the dislocation evolution on each slip system.
Anxin Ma, Franz Roters, D Raabe
exaly   +3 more sources

Estimations of bulk geometrically necessary dislocation density using high resolution EBSD

Ultramicroscopy, 2013
Characterizing the content of geometrically necessary dislocations (GNDs) in crystalline materials is crucial to understanding plasticity. Electron backscatter diffraction (EBSD) effectively recovers local crystal orientation, which is used to estimate the lattice distortion, components of the Nye dislocation density tensor (α), and subsequently the ...
David Fullwood
exaly   +3 more sources

Geometrically necessary dislocation density measurements associated with different angles of indentations

International Journal of Plasticity, 2014
Experiments and numerical simulations of various angles of wedge indenters into face-centered cubic single crystal were performed under plane strain conditions.
J W Kysar
exaly   +2 more sources

Geometrically necessary dislocation density measurements at a grain boundary due to wedge indentation into an aluminum bicrystal

Journal of the Mechanics and Physics of Solids, 2017
Abstract An aluminum bicrystal with a symmetric tilt Σ43 (3 3 5)[1 1 0] coincident site lattice grain boundary was deformed plastically via wedge indentation under conditions that led to a plane strain deformation state. Plastic deformation is induced into both crystals and the initially straight grain boundary developed a significant curvature.
J W Kysar
exaly   +2 more sources

Statistically stored, geometrically necessary and grain boundary dislocation densities: microstructural representation and modelling

Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2007
A unified physically based microstructural representation of f.c.c. crystalline materials has been developed and implemented to investigate the microstructural behaviour of f.c.c. crystalline aggregates under inelastic deformations. The proposed framework is based on coupling a multiple-slip crystal plasticity formulation to three distinct dislocation ...
M A Zikry
exaly   +2 more sources

Influence of plastic deformation heterogeneity on development of geometrically necessary dislocation density in dual phase steel

Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing, 2016
Abstract The present investigation examined the evolution of geometrically necessary dislocation (GND) structure following tensile deformation in a commercially produced dual phase steel, DP 590. GND measurements were made using electron back scatter diffraction (EBSD).
David Field, Amrita Kundu
exaly   +2 more sources

Using transmission Kikuchi diffraction in a scanning electron microscope to quantify geometrically necessary dislocation density at the nanoscale

Ultramicroscopy, 2019
It is challenging to quantify the geometrically necessary dislocation (GND) density at the nanoscale using conventional electron backscatter diffraction due to its limited spatial resolution. To overcome this problem, in this study, the transmission Kikuchi diffraction (TKD) technique is used to measure lattice orientation and to calculate the ...
Jun Jiang, Hongbiao Dong, H B Dong
exaly   +3 more sources

Estimation of geometrically necessary dislocation density from filtered EBSD data by a local linear adaptation of smoothing splines

Journal of Applied Crystallography, 2019
An implementation of smoothing splines is proposed to reduce orientation noise in electron backscatter diffraction (EBSD) data, and subsequently estimate more accurate geometrically necessary dislocation (GND) densities. The local linear adaptation of smoothing splines (LLASS) filter has two advantages over classical implementations of smoothing ...
Charbel Moussa, Marc Bernacki, Nathalie Bozzolo   +2 more
exaly   +4 more sources

Resolving localized geometrically necessary dislocation densities in Al-Mg polycrystal via in situ EBSD

Acta Materialia
The distribution of geometrically necessary dislocation (GND) densities is critical to understanding the heterogeneous plastic deformation at intragranular scales in polycrystals. In this work, we performed an in situ electron backscatter diffraction (EBSD) measurement during the tensile test on a polycrystalline Al-Mg alloy.
Hongru Zhong, Qiwei Shi, Chengyi Dan
exaly   +3 more sources

Geometrically necessary dislocation density evolution as a function of microstructure and strain rate

Materials Science and Engineering: A, 2022
Abstract The role of microstructure and strain rate on the development of geometrically necessary dislocation (GND) density in polycrystalline copper subjected to compression is assessed via crystal plasticity modelling and electron microscopy. Micropolar crystal plasticity finite element (MP-CPFE) simulations show that GND density is strongly ...
Daniel L. Foley, Marat I. Latypov, Xingyuan Zhao, Jonathan Hestroffer, Irene J. Beyerlein, Leslie E. Lamberson, Mitra L. Taheri   +6 more
openaire   +1 more source