Ab initio simulations of the structure, energetics and mobility of radiation-induced point defects in bcc Nb

Cerdeira, M.A.; Palacios, S. L.; González, César; Fernández-Pello, D.; Rodríguez, Iglesias

doi:10.1016/j.jnucmat.2016.06.013

Cited by 22 publications

(8 citation statements)

References 59 publications

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“…The vacancy formation energy in bulk Zr and bulk Nb is calculated to be 2.05 and 2.73 eV, respectively. These values are in good agreement with previous studies. − A single vacancy creates a compressive out-of-plane strain of 0.32 and 0.08% in Zr and Nb, respectively. On the other hand, one SIA induces a tensile out-of-plane strain of 0.27% in Nb, while introducing a contraction of 0.19% in the Zr crystal (see Table ).…”

Section: Results and Discussionsupporting

confidence: 92%

Interface-Driven Strain in Heavy Ion-Irradiated Zr/Nb Nanoscale Metallic Multilayers: Validation of Distortion Modeling via Local Strain Mapping

Sen

Daghbouj

Callisti

et al. 2022

ACS Appl. Mater. Interfaces

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Nanolayered metallic alloys are promising materials for nuclear applications thanks to their resistance to radiation damage. Here, we investigate the effect of ion (C, Si, and Cu) irradiation at room temperature with different fluences into sputtered Zr/Nb metallic multilayer films with periods 27 nm (thin) and 96 nm (thick). After irradiation, while a high strain in the entire thin nanoscale metallic multilayer (NMM) is observed, a quite small strain in the entire thick NMM is established. This difference is further analyzed by a semianalytical model, and the reasons behind it are revealed, which are also validated by local strain mapping. Both methods show that within a thick layer, two opposite distortions occur, making the overall strain small, whereas in a thin layer, all the atomic planes are affected by the interface and are subjected to only a single type of distortion (Nbtension and Zrcompression). In both thin and thick NMMs, with increasing damage, the strain around the interface increases, resulting in a release of the elastic energy at the interface (decrease in the lattice mismatch), and the radiation-induced transition of the Zr/Nb interfaces from incoherent to partially coherent occurs. Density functional theory simulations decipher that the inequality of point defect diffusion flux from the inner to the interface-affected region is responsible for the presence of opposite distortions within a layer. Technologically, based on this work, we estimated that Zr/Nb55 with thicknesses around Zr = 24 nm and Nb = 31 nm is the most promising multilayer system with the high radiation damage resistance and minimum swelling for nuclear applications.

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Section: Results and Discussionsupporting

confidence: 92%

Interface-Driven Strain in Heavy Ion-Irradiated Zr/Nb Nanoscale Metallic Multilayers: Validation of Distortion Modeling via Local Strain Mapping

Sen

Daghbouj

Callisti

et al. 2022

ACS Appl. Mater. Interfaces

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“…Meanwhile, the largest He displacement is observed in Nb due to an extremely low energy barrier (0.008 eV) for He migration. 43 By contrast, HEA TiZrHfMoNb has the smallest He displacement of 0.6 Å compared with the case of He in its constituents (Figure 7), agreeing well with the results of NEB calculations.…”

Section: Resultssupporting

confidence: 86%

Theoretical Combined Experimental Study of Unique He Behaviors in High-Entropy Alloys

Zhang

et al. 2021

Inorg. Chem.

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Exploring new structural materials with strong He damage tolerance is one of the key tasks for the development of nuclear reactors. Helium (He), one of the most common elements in the nuclear environment, often forms undesired bubbles in metallic materials and may result in void swelling as well as high-temperature intergranular embrittlement. In this study, the behaviors of He in high-entropy alloy (HEA) TiZrHfMoNb and its constituents are systematically investigated both theoretically and experimentally. Density functional theory calculations show that the He atom prefers to occupy tetrahedral and octahedral interstitial sites in a HEA. The migration pathway for He in TiZrHfMoNb is explored and the migration energy barrier is determined. Besides, the He clustering behavior in TiZrHfMoNb is investigated. Through transmission electron microscopy analysis, a smaller He bubble size is observed in TiZrHfMoNb than in Ti, which is proposed to result from the lower tendency to form He clusters, a weaker coarsening effect, and severe lattice distortion in HEA. The current study thus provides deep insights into the He behaviors in HEAs and may help to develop structural materials with enhanced He damage tolerance in nuclear reactors.

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“…the embedded atom method (EAM) potential of Fellinger et al (EAM-1) [41] and Cheng et al (EAM-2) [42], and the modified embedded atom method (MEAM) potential of Yang and Qi [43]. The lattice parameters, elastic constants, bulk modulus and surface energy of BCC Nb crystal obtained by these potentials are close to the experimental or first principles density functional theory (DFT) calculations values [41,[44][45][46][47]; however, these potentials are still lacking in the description of some typical point defects (such as interstitial formation energy, vacancy formation energy and migration energy) produced by irradiation, especially the predictions of the most stable interstitial formation energies that are inconsistent with the DFT results [41,48]. The DFT calculation results show that the most stable interstitial in Nb bulk is <111> dumbbell, while the most stable interstitial structures predicted by EAM-1 [41], EAM-2 [42] and MEAM [43] potentials are <110> dumbbell, <111> crowdion and <100> dumbbell, respectively.…”

Section: Introductionsupporting

confidence: 63%

“…However, the most stable interstitial structures predicted by EAM-1 [41], EAM-2 [42] and MEAM [43] are <110> dumbbell, <111> crowdion and <100> dumbbell, respectively. Figure 2 shows the overall trend of present potential predicting interstitial defects and compared with results obtained with DFT [41,48] (including the results caculated by this work) and other empirical potentials [41][42][43]. From the overall perspective of figure 2, compared with other potentials, the predicted results of the present Nb potential are closer to the DFT results.…”

Section: Validation Of the Fitted Nb Potentialmentioning

confidence: 52%

Development of a semi-empirical interatomic potential appropriate for the radiation defects in V-Ti-Ta-Nb high-entropy alloy

Qiu¹,

Chen²,

Liao³

et al. 2022

J. Phys.: Condens. Matter

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High-entropy alloys (HEAs) hold promise as candidate structural materials in future nuclear energy systems. Body-centered cubic V-Ti-Ta-Nb HEAs have received extensive attention due to their excellent mechanical properties. In this work, the Finnis-Sinclair interatomic potential for quaternary V-Ti-Ta-Nb HEAs has been fitted based on the defect properties obtained with the density functional theory (DFT) calculations. The new potential for Nb accurately reproduces the vacancy formation energy, vacancy migration energy and interstitial formation energy. The typical radiation defect properties predicted by the alloy potential were consistent with the DFT results, including the binding energies between substitutional solute atoms, the binding energy between substitutional atoms and vacancies, and the formation energy of interstitial solute atoms. In addition, the mixing enthalpies of the alloys were also consistent with the DFT results. The present potential can also describe reasonably the cascade collision process of quaternary V-Ti-Ta-Nb HEAs.

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Ab initio simulations of the structure, energetics and mobility of radiation-induced point defects in bcc Nb

Cited by 22 publications

References 59 publications

Interface-Driven Strain in Heavy Ion-Irradiated Zr/Nb Nanoscale Metallic Multilayers: Validation of Distortion Modeling via Local Strain Mapping

Interface-Driven Strain in Heavy Ion-Irradiated Zr/Nb Nanoscale Metallic Multilayers: Validation of Distortion Modeling via Local Strain Mapping

Theoretical Combined Experimental Study of Unique He Behaviors in High-Entropy Alloys

Development of a semi-empirical interatomic potential appropriate for the radiation defects in V-Ti-Ta-Nb high-entropy alloy

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