Heterogeneous nucleation of solid Al from the melt by Al 3 Ti : Molecular dynamics simulations

Handle URI:
http://hdl.handle.net/10754/598452
Title:
Heterogeneous nucleation of solid Al from the melt by Al 3 Ti : Molecular dynamics simulations
Authors:
Wang, Junsheng; Horsfield, Andrew; Lee, Peter D.; Brommer, Peter
Abstract:
It has been known experimentally for some time that Al3 Ti is a powerful nucleant for the solidification of aluminum from the melt; however, a full microscopic understanding is still lacking. To develop this understanding, we have performed molecular dynamics simulations of the nucleation and early stages of growth using published embedded atom method potentials for Al-Ti, but modified by us to stabilize the D 022 structure. We discover that Al3 Ti can indeed be very effective in promoting the growth of solid Al but the manner in which growth takes place depends sensitively on the surface on which the Al nucleates. In particular, complete growth of solid Al from the liquid on the (001) and (110) surfaces of Al3 Ti occurs at a lower temperature than on the (112) surface. This anisotropy agrees with observations in previous experiments. We explain this observation in terms of interfacial energies. On the preferential (111) surface of Al the solid-liquid interfacial energy is highest while the solid-vacuum energy is lowest. Our simulations also show that the extent of ordering taking place in liquid Al close to the Al 3 Ti substrate above the melting point correlates well with the effectiveness of the substrate as a nucleant below the melting temperature: this could provide a computationally efficient scheme to identify good nucleants. © 2010 The American Physical Society.
Citation:
Wang J, Horsfield A, Lee PD, Brommer P (2010) Heterogeneous nucleation of solid Al from the melt by Al 3 Ti  : Molecular dynamics simulations . Physical Review B 82. Available: http://dx.doi.org/10.1103/PhysRevB.82.144203.
Publisher:
American Physical Society (APS)
Journal:
Physical Review B
Issue Date:
27-Oct-2010
DOI:
10.1103/PhysRevB.82.144203
Type:
Article
ISSN:
1098-0121; 1550-235X
Sponsors:
The authors would like to acknowledge funding from King Abdullah University of Science and Technology (KAUST), and support from Thomas Young Centre (TYC) at Imperial College London. The authors also acknowledge many useful discussions both with colleagues at Imperial College London, Oak Ridge National Laboratory, and Ford Research and Advanced Engineering Laboratory and, especially Stefano Angioletti-Uberti, Mike Finnis, James R. Morris, and Mei Li and John Allison.
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Full metadata record

DC FieldValue Language
dc.contributor.authorWang, Junshengen
dc.contributor.authorHorsfield, Andrewen
dc.contributor.authorLee, Peter D.en
dc.contributor.authorBrommer, Peteren
dc.date.accessioned2016-02-25T13:20:58Zen
dc.date.available2016-02-25T13:20:58Zen
dc.date.issued2010-10-27en
dc.identifier.citationWang J, Horsfield A, Lee PD, Brommer P (2010) Heterogeneous nucleation of solid Al from the melt by Al 3 Ti  : Molecular dynamics simulations . Physical Review B 82. Available: http://dx.doi.org/10.1103/PhysRevB.82.144203.en
dc.identifier.issn1098-0121en
dc.identifier.issn1550-235Xen
dc.identifier.doi10.1103/PhysRevB.82.144203en
dc.identifier.urihttp://hdl.handle.net/10754/598452en
dc.description.abstractIt has been known experimentally for some time that Al3 Ti is a powerful nucleant for the solidification of aluminum from the melt; however, a full microscopic understanding is still lacking. To develop this understanding, we have performed molecular dynamics simulations of the nucleation and early stages of growth using published embedded atom method potentials for Al-Ti, but modified by us to stabilize the D 022 structure. We discover that Al3 Ti can indeed be very effective in promoting the growth of solid Al but the manner in which growth takes place depends sensitively on the surface on which the Al nucleates. In particular, complete growth of solid Al from the liquid on the (001) and (110) surfaces of Al3 Ti occurs at a lower temperature than on the (112) surface. This anisotropy agrees with observations in previous experiments. We explain this observation in terms of interfacial energies. On the preferential (111) surface of Al the solid-liquid interfacial energy is highest while the solid-vacuum energy is lowest. Our simulations also show that the extent of ordering taking place in liquid Al close to the Al 3 Ti substrate above the melting point correlates well with the effectiveness of the substrate as a nucleant below the melting temperature: this could provide a computationally efficient scheme to identify good nucleants. © 2010 The American Physical Society.en
dc.description.sponsorshipThe authors would like to acknowledge funding from King Abdullah University of Science and Technology (KAUST), and support from Thomas Young Centre (TYC) at Imperial College London. The authors also acknowledge many useful discussions both with colleagues at Imperial College London, Oak Ridge National Laboratory, and Ford Research and Advanced Engineering Laboratory and, especially Stefano Angioletti-Uberti, Mike Finnis, James R. Morris, and Mei Li and John Allison.en
dc.publisherAmerican Physical Society (APS)en
dc.titleHeterogeneous nucleation of solid Al from the melt by Al 3 Ti : Molecular dynamics simulationsen
dc.typeArticleen
dc.identifier.journalPhysical Review Ben
dc.contributor.institutionImperial College London, London, United Kingdomen
dc.contributor.institutionUniversitat Stuttgart, Stuttgart, Germanyen
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