Phase-Field Modeling of Chemoelastic Binodal/Spinodal Relations and Solute Segregation to Defects in Binary Alloys

Microscopic phase-field chemomechanics (MPFCM) is employed in the current work to model solute segregation, dislocation-solute interaction, spinodal decomposition, and precipitate formation, at straight dislocations and configurations of these in a model binary solid alloy. In particular, (i) a sing...

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Main Authors: Jaber Rezaei Mianroodi, Pratheek Shanthraj, Bob Svendsen, Dierk Raabe
Format: Article
Language:English
Published: MDPI AG 2021-04-01
Series:Materials
Subjects:
Online Access:https://www.mdpi.com/1996-1944/14/7/1787
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spelling doaj-c7ec3de057604d90bb22419b7dd4030f2021-04-05T23:00:09ZengMDPI AGMaterials1996-19442021-04-01141787178710.3390/ma14071787Phase-Field Modeling of Chemoelastic Binodal/Spinodal Relations and Solute Segregation to Defects in Binary AlloysJaber Rezaei Mianroodi0Pratheek Shanthraj1Bob Svendsen2Dierk Raabe3Microstructure Physics and Alloy Design, Max-Planck-Institut für Eisenforschung GmbH, 40237 Düsseldorf, GermanyThe Department of Materials, The University of Manchester, Manchester M13 9PL, UKMicrostructure Physics and Alloy Design, Max-Planck-Institut für Eisenforschung GmbH, 40237 Düsseldorf, GermanyMicrostructure Physics and Alloy Design, Max-Planck-Institut für Eisenforschung GmbH, 40237 Düsseldorf, GermanyMicroscopic phase-field chemomechanics (MPFCM) is employed in the current work to model solute segregation, dislocation-solute interaction, spinodal decomposition, and precipitate formation, at straight dislocations and configurations of these in a model binary solid alloy. In particular, (i) a single static edge dipole, (ii) arrays of static dipoles forming low-angle tilt (edge) and twist (screw) grain boundaries, as well as at (iii) a moving (gliding) edge dipole, are considered. In the first part of the work, MPFCM is formulated for such an alloy. Central here is the MPFCM model for the alloy free energy, which includes chemical, dislocation, and lattice (elastic), contributions. The solute concentration-dependence of the latter due to solute lattice misfit results in a strong elastic influence on the binodal (i.e., coexistence) and spinodal behavior of the alloy. In addition, MPFCM-based modeling of energy storage couples the thermodynamic forces driving (Cottrell and Suzuki) solute segregation, precipitate formation and dislocation glide. As implied by the simulation results for edge dislocation dipoles and their configurations, there is a competition between (i) Cottrell segregation to dislocations resulting in a uniform solute distribution along the line, and (ii) destabilization of this distribution due to low-dimensional spinodal decomposition when the segregated solute content at the line exceeds the spinodal value locally, i.e., at and along the dislocation line. Due to the completely different stress field of the screw dislocation configuration in the twist boundary, the segregated solute distribution is immediately unstable and decomposes into precipitates from the start.https://www.mdpi.com/1996-1944/14/7/1787phase-field chemomechanicssolute segregationspinodal decompositiondislocation-solute interactionlow angle grain boundary
collection DOAJ
language English
format Article
sources DOAJ
author Jaber Rezaei Mianroodi
Pratheek Shanthraj
Bob Svendsen
Dierk Raabe
spellingShingle Jaber Rezaei Mianroodi
Pratheek Shanthraj
Bob Svendsen
Dierk Raabe
Phase-Field Modeling of Chemoelastic Binodal/Spinodal Relations and Solute Segregation to Defects in Binary Alloys
Materials
phase-field chemomechanics
solute segregation
spinodal decomposition
dislocation-solute interaction
low angle grain boundary
author_facet Jaber Rezaei Mianroodi
Pratheek Shanthraj
Bob Svendsen
Dierk Raabe
author_sort Jaber Rezaei Mianroodi
title Phase-Field Modeling of Chemoelastic Binodal/Spinodal Relations and Solute Segregation to Defects in Binary Alloys
title_short Phase-Field Modeling of Chemoelastic Binodal/Spinodal Relations and Solute Segregation to Defects in Binary Alloys
title_full Phase-Field Modeling of Chemoelastic Binodal/Spinodal Relations and Solute Segregation to Defects in Binary Alloys
title_fullStr Phase-Field Modeling of Chemoelastic Binodal/Spinodal Relations and Solute Segregation to Defects in Binary Alloys
title_full_unstemmed Phase-Field Modeling of Chemoelastic Binodal/Spinodal Relations and Solute Segregation to Defects in Binary Alloys
title_sort phase-field modeling of chemoelastic binodal/spinodal relations and solute segregation to defects in binary alloys
publisher MDPI AG
series Materials
issn 1996-1944
publishDate 2021-04-01
description Microscopic phase-field chemomechanics (MPFCM) is employed in the current work to model solute segregation, dislocation-solute interaction, spinodal decomposition, and precipitate formation, at straight dislocations and configurations of these in a model binary solid alloy. In particular, (i) a single static edge dipole, (ii) arrays of static dipoles forming low-angle tilt (edge) and twist (screw) grain boundaries, as well as at (iii) a moving (gliding) edge dipole, are considered. In the first part of the work, MPFCM is formulated for such an alloy. Central here is the MPFCM model for the alloy free energy, which includes chemical, dislocation, and lattice (elastic), contributions. The solute concentration-dependence of the latter due to solute lattice misfit results in a strong elastic influence on the binodal (i.e., coexistence) and spinodal behavior of the alloy. In addition, MPFCM-based modeling of energy storage couples the thermodynamic forces driving (Cottrell and Suzuki) solute segregation, precipitate formation and dislocation glide. As implied by the simulation results for edge dislocation dipoles and their configurations, there is a competition between (i) Cottrell segregation to dislocations resulting in a uniform solute distribution along the line, and (ii) destabilization of this distribution due to low-dimensional spinodal decomposition when the segregated solute content at the line exceeds the spinodal value locally, i.e., at and along the dislocation line. Due to the completely different stress field of the screw dislocation configuration in the twist boundary, the segregated solute distribution is immediately unstable and decomposes into precipitates from the start.
topic phase-field chemomechanics
solute segregation
spinodal decomposition
dislocation-solute interaction
low angle grain boundary
url https://www.mdpi.com/1996-1944/14/7/1787
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