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Modelling defects in Ni-Al with EAM and DFT calculations
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Bianchini, Federico, Kermode, James R. and De Vita, Alessandro (2016) Modelling defects in Ni-Al with EAM and DFT calculations. Modelling and Simulation in Materials Science and Engineering, 24 (4). 045012. doi:10.1088/0965-0393/24/4/045012
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Official URL: http://dx.doi.org/10.1088/0965-0393/24/4/045012
Abstract
We present detailed comparisons between the results of embedded atom model (EAM) and density functional theory (DFT) calculations on defected Ni alloy systems. We find that the EAM interatomic potentials reproduce low-temperature structural properties in both the γ and ${{\gamma}^{\prime}}$ phases, and yield accurate atomic forces in bulk-like configurations even at temperatures as high as ~1200 K. However, they fail to describe more complex chemical bonding, in configurations including defects such as vacancies or dislocations, for which we observe significant deviations between the EAM and DFT forces, suggesting that derived properties such as (free) energy barriers to vacancy migration and dislocation glide may also be inaccurate. Testing against full DFT calculations further reveals that these deviations have a local character, and are typically severe only up to the first or second neighbours of the defect. This suggests that a QM/MM approach can be used to accurately reproduce QM observables, fully exploiting the EAM potential efficiency in the MM zone. This approach could be easily extended to ternary systems for which developing a reliable and fully transferable EAM parameterisation would be extremely challenging e.g. Ni alloy model systems with a W or Re-containing QM zone.
| Item Type: | Journal Article | |||||||||||||||
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| Subjects: | T Technology > TA Engineering (General). Civil engineering (General) | |||||||||||||||
| Divisions: | Faculty of Science > Engineering | |||||||||||||||
| Library of Congress Subject Headings (LCSH): | Nickel alloys -- Testing, Density functionals | |||||||||||||||
| Journal or Publication Title: | Modelling and Simulation in Materials Science and Engineering | |||||||||||||||
| Publisher: | Institute of Physics Publishing Ltd. | |||||||||||||||
| ISSN: | 0965-0393 | |||||||||||||||
| Official Date: | 18 April 2016 | |||||||||||||||
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| Volume: | 24 | |||||||||||||||
| Number: | 4 | |||||||||||||||
| Article Number: | 045012 | |||||||||||||||
| DOI: | 10.1088/0965-0393/24/4/045012 | |||||||||||||||
| Status: | Peer Reviewed | |||||||||||||||
| Publication Status: | Published | |||||||||||||||
| Access rights to Published version: | Open Access | |||||||||||||||
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