Strain-Gradient Crystal Plasticity Finite Element Modeling of Slip Band Formation in α-Zirconium

Two methods for the determination of geometrically necessary dislocation (GND) densities are implemented in a lower-order strain-gradient crystal plasticity finite element model. The equations are implemented in user material (UMAT) subroutines. Method I has a direct and unique solution for the dens...

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Autores principales:	Omid Sedaghat, Hamidreza Abdolvand
Formato:	article
Lenguaje:	EN
Publicado:	MDPI AG 2021
Materias:	zirconium strain-gradient crystal plasticity slip band geometrically necessary dislocation statistically stored dislocation high angular resolution electron back scatter diffraction Crystallography QD901-999
Acceso en línea:	https://doaj.org/article/e2d61e89a43147399c57b5499c8475b9
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spelling	oai:doaj.org-article:e2d61e89a43147399c57b5499c8475b92021-11-25T17:19:10ZStrain-Gradient Crystal Plasticity Finite Element Modeling of Slip Band Formation in α-Zirconium10.3390/cryst111113822073-4352https://doaj.org/article/e2d61e89a43147399c57b5499c8475b92021-11-01T00:00:00Zhttps://www.mdpi.com/2073-4352/11/11/1382https://doaj.org/toc/2073-4352Two methods for the determination of geometrically necessary dislocation (GND) densities are implemented in a lower-order strain-gradient crystal plasticity finite element model. The equations are implemented in user material (UMAT) subroutines. Method I has a direct and unique solution for the density of GNDs, while Method II has unlimited solutions, where an optimization technique is used to determine GND densities. The performance of each method for capturing the formation of slip bands based on the calculated GND maps is critically analyzed. First, the model parameters are identified using single crystal simulations. This is followed by importing the as-measured microstructure for a deformed α-zirconium specimen into the finite element solver to compare the numerical results obtained from the models to those measured experimentally using the high angular resolution electron backscatter diffraction technique. It is shown that both methods are capable of modeling the formation of slip bands that are parallel to those observed experimentally. Formation of such bands is observed in both GND maps and plastic shear strain maps without pre-determining the slip band domain. Further, there is a negligible difference between the calculated grain-scale stresses and elastic lattice rotations from the two methods, where the modeling results are close to the measured ones. However, the magnitudes and distributions of calculated GND densities from the two methods are very different.Omid SedaghatHamidreza AbdolvandMDPI AGarticlezirconiumstrain-gradient crystal plasticityslip bandgeometrically necessary dislocationstatistically stored dislocationhigh angular resolution electron back scatter diffractionCrystallographyQD901-999ENCrystals, Vol 11, Iss 1382, p 1382 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	zirconium strain-gradient crystal plasticity slip band geometrically necessary dislocation statistically stored dislocation high angular resolution electron back scatter diffraction Crystallography QD901-999
spellingShingle	zirconium strain-gradient crystal plasticity slip band geometrically necessary dislocation statistically stored dislocation high angular resolution electron back scatter diffraction Crystallography QD901-999 Omid Sedaghat Hamidreza Abdolvand Strain-Gradient Crystal Plasticity Finite Element Modeling of Slip Band Formation in α-Zirconium
description	Two methods for the determination of geometrically necessary dislocation (GND) densities are implemented in a lower-order strain-gradient crystal plasticity finite element model. The equations are implemented in user material (UMAT) subroutines. Method I has a direct and unique solution for the density of GNDs, while Method II has unlimited solutions, where an optimization technique is used to determine GND densities. The performance of each method for capturing the formation of slip bands based on the calculated GND maps is critically analyzed. First, the model parameters are identified using single crystal simulations. This is followed by importing the as-measured microstructure for a deformed α-zirconium specimen into the finite element solver to compare the numerical results obtained from the models to those measured experimentally using the high angular resolution electron backscatter diffraction technique. It is shown that both methods are capable of modeling the formation of slip bands that are parallel to those observed experimentally. Formation of such bands is observed in both GND maps and plastic shear strain maps without pre-determining the slip band domain. Further, there is a negligible difference between the calculated grain-scale stresses and elastic lattice rotations from the two methods, where the modeling results are close to the measured ones. However, the magnitudes and distributions of calculated GND densities from the two methods are very different.
format	article
author	Omid Sedaghat Hamidreza Abdolvand
author_facet	Omid Sedaghat Hamidreza Abdolvand
author_sort	Omid Sedaghat
title	Strain-Gradient Crystal Plasticity Finite Element Modeling of Slip Band Formation in α-Zirconium
title_short	Strain-Gradient Crystal Plasticity Finite Element Modeling of Slip Band Formation in α-Zirconium
title_full	Strain-Gradient Crystal Plasticity Finite Element Modeling of Slip Band Formation in α-Zirconium
title_fullStr	Strain-Gradient Crystal Plasticity Finite Element Modeling of Slip Band Formation in α-Zirconium
title_full_unstemmed	Strain-Gradient Crystal Plasticity Finite Element Modeling of Slip Band Formation in α-Zirconium
title_sort	strain-gradient crystal plasticity finite element modeling of slip band formation in α-zirconium
publisher	MDPI AG
publishDate	2021
url	https://doaj.org/article/e2d61e89a43147399c57b5499c8475b9
work_keys_str_mv	AT omidsedaghat straingradientcrystalplasticityfiniteelementmodelingofslipbandformationinazirconium AT hamidrezaabdolvand straingradientcrystalplasticityfiniteelementmodelingofslipbandformationinazirconium
_version_	1718412564702953472

Strain-Gradient Crystal Plasticity Finite Element Modeling of Slip Band Formation in α-Zirconium

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