Thermodiffusion in liquid binary alloys computed from molecular-dynamics simulation and the Green-Kubo formalism.
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| Title: | Thermodiffusion in liquid binary alloys computed from molecular-dynamics simulation and the Green-Kubo formalism. |
|---|---|
| Authors: | Tucker, William C.1, Schelling, Patrick K.1 patrick.schelling@ucf.edu |
| Source: | Computational Materials Science. Nov2016, Vol. 124, p54-61. 8p. |
| Subjects: | Binary metallic systems, Thermophoresis, Molecular dynamics, Liquid alloys, Temperature effect |
| Abstract: | In the presence of a temperature gradient, the components of a binary liquid tend to segregate. This phenomenon, generally referred to as thermodiffusion or the Soret effect, is usually quantified by the heat of transport. We report heat of transport values Q c ∗ for NiAl and NiCu melts computed using molecular-dynamics simulation and the Green-Kubo formalism. Thermal conductivities are also reported. To develop a clear picture of the phenomena, we determined contributions to Q c ∗ due to the convective and virial components of the heat current, which were then compared to the related terms in the partial enthalpy. It is shown that the contribution to Q c ∗ from the convective component of the heat current is comparable to the average energy of the diffusing atoms, differing by an amount comparable to the activation energy for diffusion. The contribution to Q c ∗ from the virial heat current is closely related to the pressure-volume term p c Ω in the partial enthalpy. It is established that the virial heat current plays a dominant role in determining the sign of the reduced heat of transport Q c ∗ ′ = Q c ∗ - h c . By comparing results obtained with different empirical potentials, a trend emerges. Specifically, it is found that the sign of the reduced heat of transport is correlated with the sign of the partial pressure associated with the low-mass component. It is also shown that two different empirical potentials for the NiAl system give vastly different results for Q c ∗ ′ . The results indicate that in developing a potential that might accurately predict Q c ∗ ′ , the distribution of the partial energy and partial pressure between the two components is critical. Based on these observations, it would appear that existing empirical potentials may not be able to generate reliable predictions for Q c ∗ ′ without additional validation. [ABSTRACT FROM AUTHOR] |
| Copyright of Computational Materials Science is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
| FullText | Text: Availability: 0 |
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| Header | DbId: egs DbLabel: Engineering Source An: 117835671 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Thermodiffusion in liquid binary alloys computed from molecular-dynamics simulation and the Green-Kubo formalism. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Tucker%2C+William+C%2E%22">Tucker, William C.</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Schelling%2C+Patrick+K%2E%22">Schelling, Patrick K.</searchLink><relatesTo>1</relatesTo><i> patrick.schelling@ucf.edu</i> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Computational+Materials+Science%22">Computational Materials Science</searchLink>. Nov2016, Vol. 124, p54-61. 8p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Binary+metallic+systems%22">Binary metallic systems</searchLink><br /><searchLink fieldCode="DE" term="%22Thermophoresis%22">Thermophoresis</searchLink><br /><searchLink fieldCode="DE" term="%22Molecular+dynamics%22">Molecular dynamics</searchLink><br /><searchLink fieldCode="DE" term="%22Liquid+alloys%22">Liquid alloys</searchLink><br /><searchLink fieldCode="DE" term="%22Temperature+effect%22">Temperature effect</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: In the presence of a temperature gradient, the components of a binary liquid tend to segregate. This phenomenon, generally referred to as thermodiffusion or the Soret effect, is usually quantified by the heat of transport. We report heat of transport values Q c ∗ for NiAl and NiCu melts computed using molecular-dynamics simulation and the Green-Kubo formalism. Thermal conductivities are also reported. To develop a clear picture of the phenomena, we determined contributions to Q c ∗ due to the convective and virial components of the heat current, which were then compared to the related terms in the partial enthalpy. It is shown that the contribution to Q c ∗ from the convective component of the heat current is comparable to the average energy of the diffusing atoms, differing by an amount comparable to the activation energy for diffusion. The contribution to Q c ∗ from the virial heat current is closely related to the pressure-volume term p c Ω in the partial enthalpy. It is established that the virial heat current plays a dominant role in determining the sign of the reduced heat of transport Q c ∗ ′ = Q c ∗ - h c . By comparing results obtained with different empirical potentials, a trend emerges. Specifically, it is found that the sign of the reduced heat of transport is correlated with the sign of the partial pressure associated with the low-mass component. It is also shown that two different empirical potentials for the NiAl system give vastly different results for Q c ∗ ′ . The results indicate that in developing a potential that might accurately predict Q c ∗ ′ , the distribution of the partial energy and partial pressure between the two components is critical. Based on these observations, it would appear that existing empirical potentials may not be able to generate reliable predictions for Q c ∗ ′ without additional validation. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Computational Materials Science is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1016/j.commatsci.2016.07.012 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 8 StartPage: 54 Subjects: – SubjectFull: Binary metallic systems Type: general – SubjectFull: Thermophoresis Type: general – SubjectFull: Molecular dynamics Type: general – SubjectFull: Liquid alloys Type: general – SubjectFull: Temperature effect Type: general Titles: – TitleFull: Thermodiffusion in liquid binary alloys computed from molecular-dynamics simulation and the Green-Kubo formalism. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Tucker, William C. – PersonEntity: Name: NameFull: Schelling, Patrick K. IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 11 Text: Nov2016 Type: published Y: 2016 Identifiers: – Type: issn-print Value: 09270256 Numbering: – Type: volume Value: 124 Titles: – TitleFull: Computational Materials Science Type: main |
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