| 1. |
- De Backer, A., et al.
(author)
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Primary damage in tungsten using the binary collision approximation, molecular dynamic simulations and the density functional theory
- 2016
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In: Physica Scripta. - : Institute of Physics Publishing (IOPP). - 0031-8949 .- 1402-4896. ; T167
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Journal article (peer-reviewed)abstract
- The damage produced by primary knock-on atoms (PKA) in W has been investigated from the threshold displacement energy (TDE) where it produces one self interstitial atom-vacancy pair to larger energies, up to 100 keV, where a large molten volume is formed. The TDE has been determined in different crystal directions using the Born-Oppenheimer density functional molecular dynamics (DFT-MD). A significant difference has been observed without and with the semi-core electrons. Classical MD has been used with two different empirical potentials characterized as 'soft' and 'hard' to obtain statistics on TDEs. Cascades of larger energy have been calculated, with these potentials, using a model that accounts for electronic losses (Sand et al 2013 Europhys. Lett. 103 46003). Two other sets of cascades have been produced using the binary collision approximation (BCA): a Monte Carlo BCA using SDTrimSP (Eckstein et al 2011 SDTrimSP: Version 5.00. Report IPP 12/8) (similar to SRIM www.srim.org) and MARLOWE (RSICC Home Page. (https://rsicc.ornl.gov/codes/psr/psr1/psr-137.html) (accessed May, 2014)). The comparison of these sets of cascades gave a recombination distance equal to 12 angstrom which is significantly larger from the one we reported in Hou et al (2010 J. Nucl. Mater. 403 89) because, here, we used bulk cascades rather than surface cascades which produce more defects (Stoller 2002 J. Nucl. Mater. 307 935, Nordlund et al 1999 Nature 398 49). Investigations on the defect clustering aspect showed that the difference between BCA and MD cascades is considerably reduced after the annealing of the cascade debris at 473 K using our Object Kinetic Monte Carlo model, LAKIMOCA.
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| 2. |
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| 3. |
- Becquart, C. S., et al.
(author)
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A DFT study of the stability of SIAs and small SIA clusters in the vicinity of solute atoms in Fe
- 2018
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In: Journal of Nuclear Materials. - : Elsevier B.V.. - 0022-3115 .- 1873-4820. ; 500, s. 92-109
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Journal article (peer-reviewed)abstract
- The energetics, defect volume and magnetic properties of single SIAs and small SIA clusters up to size 6 have been calculated by DFT for different configurations like the parallel 〈110〉 dumbbell, the non parallel 〈110〉 dumbbell and the C15 structure. The most stable configurations of each type have been further analyzed to determine the influence on their stability of various solute atoms (Ti, V, Cr, Mn, Co, Ni, Cu, Mo, W, Pd, Al, Si, P), relevant for steels used under irradiation. The results show that the presence of solute atoms does not change the relative stability order among SIA clusters. The small SIA clusters investigated can bind to both undersized and oversized solutes. Several descriptors have been considered to derive interesting trends from results. It appears that the local atomic volume available for the solute is the main physical quantity governing the binding energy evolution, whatever the solute type (undersized or oversized) and the cluster configuration (size and type).
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| 4. |
- Olsson, Pär, et al.
(author)
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Ab initio threshold displacement energies in iron
- 2016
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In: Materials Research Letters. - : Taylor & Francis. - 2166-3831. ; 4:4, s. 219-225
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Journal article (peer-reviewed)abstract
- The threshold displacement energy in iron is determined using ab initio molecular dynamics. This is the most fundamental input parameter for radiation damage assessments. The predictions agree well with the available experiments and provide a significantly lower average value for iron than the standard one. This result impacts radiation damage assessments in iron alloys and steels and especially so for dose estimations and conditions close to the threshold. The importance of using an appropriate description of the core and valence electrons is highlighted. Energy loss simulations provide important fitting parameters for improved interatomic potentials. IMPACT STATEMENT Ground-breaking ab initio calculations of the threshold displacement energies in iron show significant differences in the angular anisotropy and predicted average value with respect to previous literature.
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