Theoretical framework for predicting solute concentrations and solute-induced stresses in finite volumes with arbitrary elastic fields

Abstract A theoretical model for computing the interstitial solute concentration and the interstitial solute-induced stress field in a three-dimensional finite medium with any arbitrary elastic fields was developed. This model can be directly incorporated into two-dimensional or three-dimensional di...

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Main Authors: Yejun Gu, Jaafar A. El-Awady
Format: Article
Language:English
Published: SpringerOpen 2020-04-01
Series:Materials Theory
Subjects:
Online Access:http://link.springer.com/article/10.1186/s41313-020-00020-2
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author Yejun Gu
Jaafar A. El-Awady
author_facet Yejun Gu
Jaafar A. El-Awady
author_sort Yejun Gu
collection DOAJ
description Abstract A theoretical model for computing the interstitial solute concentration and the interstitial solute-induced stress field in a three-dimensional finite medium with any arbitrary elastic fields was developed. This model can be directly incorporated into two-dimensional or three-dimensional discrete dislocation dynamics simulations, continuum dislocation dynamics simulations, or crystal plasticity simulations. Using this model, it is shown that a nano-hydride can form in the tensile region below a dissociated edge dislocation at hydrogen concentration as low as χ 0=5×10−5, and its formation induces a localized hydrogen elastic shielding effect that leads to a lower stacking fault width for the edge dislocation. Additionally, the model also predicts the segregation of hydrogen at Σ109(13 7 0)/33.4∘ symmetric tilt grain boundary dislocations. This segregation strongly alters the magnitude of the shear stresses at the grain boundary, which can subsequently alter dislocation-grain boundary interactions and dislocation slip transmissions across the grain boundary. Moreover, the model also predicts that the hydrogen concentration at a mode-I central crack tip increases with increasing external loading, higher intrinsic hydrogen concentration, and/or larger crack lengths. Finally, linearized approximate closed-form solutions for the solute concentration and the interstitial solute-induced stress field were also developed. These approximate solutions can effectively reduce the computation cost to assess the concentration and stress field in the presence of solutes. These approximate solutions are also shown to be a good approximation when the positions of interest are several nanometers away (i.e. long-ranged elastic interactions) from stress singularities (e.g. dislocation core and crack tip), for low solute concentrations, and/or at high temperatures.
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spelling doaj.art-bdfb5375ff5947e6b4dd0fae6588c5022022-12-21T21:51:58ZengSpringerOpenMaterials Theory2509-80122020-04-014112210.1186/s41313-020-00020-2Theoretical framework for predicting solute concentrations and solute-induced stresses in finite volumes with arbitrary elastic fieldsYejun Gu0Jaafar A. El-Awady1Department of Mechanical Engineering, Whiting School of Engineering, The Johns Hopkins UniversityDepartment of Mechanical Engineering, Whiting School of Engineering, The Johns Hopkins UniversityAbstract A theoretical model for computing the interstitial solute concentration and the interstitial solute-induced stress field in a three-dimensional finite medium with any arbitrary elastic fields was developed. This model can be directly incorporated into two-dimensional or three-dimensional discrete dislocation dynamics simulations, continuum dislocation dynamics simulations, or crystal plasticity simulations. Using this model, it is shown that a nano-hydride can form in the tensile region below a dissociated edge dislocation at hydrogen concentration as low as χ 0=5×10−5, and its formation induces a localized hydrogen elastic shielding effect that leads to a lower stacking fault width for the edge dislocation. Additionally, the model also predicts the segregation of hydrogen at Σ109(13 7 0)/33.4∘ symmetric tilt grain boundary dislocations. This segregation strongly alters the magnitude of the shear stresses at the grain boundary, which can subsequently alter dislocation-grain boundary interactions and dislocation slip transmissions across the grain boundary. Moreover, the model also predicts that the hydrogen concentration at a mode-I central crack tip increases with increasing external loading, higher intrinsic hydrogen concentration, and/or larger crack lengths. Finally, linearized approximate closed-form solutions for the solute concentration and the interstitial solute-induced stress field were also developed. These approximate solutions can effectively reduce the computation cost to assess the concentration and stress field in the presence of solutes. These approximate solutions are also shown to be a good approximation when the positions of interest are several nanometers away (i.e. long-ranged elastic interactions) from stress singularities (e.g. dislocation core and crack tip), for low solute concentrations, and/or at high temperatures.http://link.springer.com/article/10.1186/s41313-020-00020-2Interstitial solutesHydrogen embrittlementSegregationDislocation dynamicsSolute diffusion
spellingShingle Yejun Gu
Jaafar A. El-Awady
Theoretical framework for predicting solute concentrations and solute-induced stresses in finite volumes with arbitrary elastic fields
Materials Theory
Interstitial solutes
Hydrogen embrittlement
Segregation
Dislocation dynamics
Solute diffusion
title Theoretical framework for predicting solute concentrations and solute-induced stresses in finite volumes with arbitrary elastic fields
title_full Theoretical framework for predicting solute concentrations and solute-induced stresses in finite volumes with arbitrary elastic fields
title_fullStr Theoretical framework for predicting solute concentrations and solute-induced stresses in finite volumes with arbitrary elastic fields
title_full_unstemmed Theoretical framework for predicting solute concentrations and solute-induced stresses in finite volumes with arbitrary elastic fields
title_short Theoretical framework for predicting solute concentrations and solute-induced stresses in finite volumes with arbitrary elastic fields
title_sort theoretical framework for predicting solute concentrations and solute induced stresses in finite volumes with arbitrary elastic fields
topic Interstitial solutes
Hydrogen embrittlement
Segregation
Dislocation dynamics
Solute diffusion
url http://link.springer.com/article/10.1186/s41313-020-00020-2
work_keys_str_mv AT yejungu theoreticalframeworkforpredictingsoluteconcentrationsandsoluteinducedstressesinfinitevolumeswitharbitraryelasticfields
AT jaafaraelawady theoreticalframeworkforpredictingsoluteconcentrationsandsoluteinducedstressesinfinitevolumeswitharbitraryelasticfields