<i>Ab initio</i>scaling laws for the formation energy of nanosized interstitial defect clusters in iron, tungsten, and vanadium

Alexander, Rebecca; Marinica, Mihai-Cosmin; Proville, Laurent; Willaime, F.; Arakawa, Kazuto; Gilbert, Mark R.; Dudarev, S. L.

doi:10.1103/physrevb.94.024103

Cited by 96 publications

(124 citation statements)

References 62 publications

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“…For tungsten, the majority of existing potentials struggle to reproduce the correct trend of the relative stability of clusters of multiple SIAs. For example, several widely used EAM potentials predict dislocation loops with the Burgers vector 1 0 0 to be lower in energy than the 1/2 1 1 1 loops [5], which is in clear contradiction to DFT [82] and experimental observations [83,84]. We therefore put particular focus on ensuring that our GAP reproduces the expected trend obtained by DFT.…”

Section: Self-interstitial Atoms and Clustersmentioning

confidence: 90%

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Machine-learning interatomic potential for radiation damage and defects in tungsten

et al. 2019

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We introduce a machine-learning interatomic potential for tungsten using the Gaussian Approximation Potential framework. We specifically focus on properties relevant for simulations of radiationinduced collision cascades and the damage they produce, including a realistic repulsive potential for the short-range many-body cascade dynamics and a good description of the liquid phase. Furthermore, the potential accurately reproduces surface properties and the energetics of vacancy and self-interstitial clusters, which have been long-standing deficiencies of existing potentials. The potential enables molecular dynamics simulations of radiation damage in tungsten with unprecedented accuracy.

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Section: Self-interstitial Atoms and Clustersmentioning

confidence: 90%

“…13 shows formation energies of parallel 1 1 1 and 1 0 0 SIA clusters (i.e. dislocation loops) compared between the GAP and DFT data from [82]. 1/2 1 1 1 clusters are created by inserting parallel dumbbells with a (1 1 0) habit plane, and 1 0 0 with a (1 0 0) plane, as in [82].…”

Section: Self-interstitial Atoms and Clustersmentioning

confidence: 99%

Machine-learning interatomic potential for radiation damage and defects in tungsten

et al. 2019

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“…2.37 ± 0.06 7.39 ± 0.20 4.92 ± 0.29 1.22 ± 0.01 0.39 ± 0.03 0.87 ± 0.04 Table 7: Linear regression fits for the formation energy (in eV) and relaxation volume Ω rel /Ω 0 of interstitial clusters in the C15 structure. Energies are fitted to E f = a 0 N +a 1 N 2/3 +a 2 , as suggested by ref [52], indicating terms dependent on volume and surface area. Relaxation volume are fitted to Ω rel /Ω 0 = b 0 N + b 1 N 2/3 + b 2 .…”

Section: The Anisotropy Of the Elastic Relaxationmentioning

confidence: 99%

“…Relaxation volume are fitted to Ω rel /Ω 0 = b 0 N + b 1 N 2/3 + b 2 . The structures taken were those used in ref [52], using the cell relaxation method, with sizes 2 ≤ N ≤ 22. 4).…”

Section: The Anisotropy Of the Elastic Relaxationmentioning

confidence: 99%

Relaxation volumes of microscopic and mesoscopic irradiation-induced defects in tungsten

Mason

Nguyen-Manh

Marinica

et al. 2019

Journal of Applied Physics

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The low energy structures of irradiation-induced defects have been studied in detail, as these determine the available modes by which a defect can diffuse or relax. As a result, there are many studies concerning the relative energies of possible defect structures, and empirical potentials are commonly fitted to or evaluated with respect to these energies. But recently [Dudarev et. al. Nuclear Fusion 2018], we have shown how to determine the stresses, strains and swelling of reactor components under irradiation from the elastic properties of ensembles of irradiation-induced defects. These elastic properties have received comparatively little attention. Here we evaluate relaxation volumes of irradiation-induced defects in tungsten computed with empirical potentials, and compare to density functional theory results where available. Different empirical potentials give different results, but some potential-independent trends in relaxation volumes can be identified. We show that the relaxation volume of small defects can be predicted to within 10% from their point-defect count. For larger defects we provide empirical fits for the relaxation volume of as a function of size. We demonstrate that the relaxation volume associated * daniel.mason@ukaea.uk arXiv:1812.06874v1 [cond-mat.mtrl-sci] 17 Dec 2018 with a single primary-damage cascade can be estimated from the primary knock-on atom (PKA) energy. We conclude that while annihilation of vacancy-and interstitial-character defects will invariably reduce the total relaxation volume of the cascade debris, empirical potentials disagree whether coalescence of defects will reduce or increase the total relaxation volume.

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“…The bottom figure shows similar histograms for cluster sizes 2-13 interstitials. Inset: a comparison of the binding energy for the minimum energy structures computed with DFT[74]…”

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confidence: 99%

Atomistic-object kinetic Monte Carlo simulations of irradiation damage in tungsten

Mason

Sand

Dudarev

2019

Modelling Simul. Mater. Sci. Eng.

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We describe the development of a new object kinetic Monte Carlo code where the elementary defect objects are off-lattice atomistic configurations. Atomic-level transitions are used to transform and translate objects, to split objects and to merge them together. This gradually constructs a database of atomic configurations-a set of relevant defect objects and their possible events generated on-the-fly. Elastic interactions are handled within objects with empirical potentials at short distances, and between spatially distinct objects using the dipole tensor formalism. The model is shown to evolve mobile interstitial clusters in tungsten faster than an equivalent molecular dynamics simulation, even at elevated temperatures. We apply the model to the evolution of complex defects generated using molecular dynamics simulations of primary radiation damage in tungsten. We show that we can evolve defect structures formed in cascade simulations to experimentally observable timescales of seconds while retaining atomistic detail. We conclude that the first few nanoseconds of simulation following cascade initiation would be better performed using molecular dynamics, as this will capture some of the near-temperatureindependent evolution of small highly-mobile interstitial clusters. We also conclude that, for the 20keV PKA cascades annealing simulations considered here, internal relaxations of sessile objects difficult to capture using conventional object KMC with idealised object geometries establish the conditions for long timescale evolution.

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Ab initioscaling laws for the formation energy of nanosized interstitial defect clusters in iron, tungsten, and vanadium

Cited by 96 publications

References 62 publications

Machine-learning interatomic potential for radiation damage and defects in tungsten

Machine-learning interatomic potential for radiation damage and defects in tungsten

Relaxation volumes of microscopic and mesoscopic irradiation-induced defects in tungsten

Atomistic-object kinetic Monte Carlo simulations of irradiation damage in tungsten

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