Crystal Plasticity Modeling of Dislocation Density Evolution in Cellular Dislocation Structures

The complex thermal cycles during the solidification process in metal additive manufacturing (AM) lead to the formation of high-density dislocation networks, organizing into submicron-scale cellular structures. These ultrafine structures are recognized as crucial for enhancing the mechanical propert...

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Main Authors: Md Mahabubur Rohoman, Caizhi Zhou
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Metals
Subjects:
Online Access:https://www.mdpi.com/2075-4701/15/4/419
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author Md Mahabubur Rohoman
Caizhi Zhou
author_facet Md Mahabubur Rohoman
Caizhi Zhou
author_sort Md Mahabubur Rohoman
collection DOAJ
description The complex thermal cycles during the solidification process in metal additive manufacturing (AM) lead to the formation of high-density dislocation networks, organizing into submicron-scale cellular structures. These ultrafine structures are recognized as crucial for enhancing the mechanical properties of AM metals. In this study, we investigate the evolution of dislocation density within these cellular structures under plastic deformation and its impact on mechanical response using dislocation density-based crystal plasticity finite element (CPFE) modeling. The model incorporates the evolution of both statistically stored dislocation (SSD) and geometrically necessary dislocation (GND). Our simulations reveal that the yield and flow stresses of dislocation cell structures exceed predictions based on the rule of mixtures (ROM). Additionally, the SSD density increases at a higher rate than the GND density. Factors such as the volume fraction of the cell wall, cell diameter, and initial dislocation density difference between the cell wall and interior significantly influence GND accumulation across different regions of the cellular dislocation structures.
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spelling doaj-art-79df834b0a494c078e1d8725ecb5646e2025-08-20T03:13:58ZengMDPI AGMetals2075-47012025-04-0115441910.3390/met15040419Crystal Plasticity Modeling of Dislocation Density Evolution in Cellular Dislocation StructuresMd Mahabubur Rohoman0Caizhi Zhou1Department of Mechanical Engineering, University of South Carolina, Columbia, SC 29208, USADepartment of Mechanical Engineering, University of South Carolina, Columbia, SC 29208, USAThe complex thermal cycles during the solidification process in metal additive manufacturing (AM) lead to the formation of high-density dislocation networks, organizing into submicron-scale cellular structures. These ultrafine structures are recognized as crucial for enhancing the mechanical properties of AM metals. In this study, we investigate the evolution of dislocation density within these cellular structures under plastic deformation and its impact on mechanical response using dislocation density-based crystal plasticity finite element (CPFE) modeling. The model incorporates the evolution of both statistically stored dislocation (SSD) and geometrically necessary dislocation (GND). Our simulations reveal that the yield and flow stresses of dislocation cell structures exceed predictions based on the rule of mixtures (ROM). Additionally, the SSD density increases at a higher rate than the GND density. Factors such as the volume fraction of the cell wall, cell diameter, and initial dislocation density difference between the cell wall and interior significantly influence GND accumulation across different regions of the cellular dislocation structures.https://www.mdpi.com/2075-4701/15/4/419crystal plasticitymicrostructureadditive manufacturingdislocation celldislocation densityfinite element method
spellingShingle Md Mahabubur Rohoman
Caizhi Zhou
Crystal Plasticity Modeling of Dislocation Density Evolution in Cellular Dislocation Structures
Metals
crystal plasticity
microstructure
additive manufacturing
dislocation cell
dislocation density
finite element method
title Crystal Plasticity Modeling of Dislocation Density Evolution in Cellular Dislocation Structures
title_full Crystal Plasticity Modeling of Dislocation Density Evolution in Cellular Dislocation Structures
title_fullStr Crystal Plasticity Modeling of Dislocation Density Evolution in Cellular Dislocation Structures
title_full_unstemmed Crystal Plasticity Modeling of Dislocation Density Evolution in Cellular Dislocation Structures
title_short Crystal Plasticity Modeling of Dislocation Density Evolution in Cellular Dislocation Structures
title_sort crystal plasticity modeling of dislocation density evolution in cellular dislocation structures
topic crystal plasticity
microstructure
additive manufacturing
dislocation cell
dislocation density
finite element method
url https://www.mdpi.com/2075-4701/15/4/419
work_keys_str_mv AT mdmahabuburrohoman crystalplasticitymodelingofdislocationdensityevolutionincellulardislocationstructures
AT caizhizhou crystalplasticitymodelingofdislocationdensityevolutionincellulardislocationstructures