Kinetic Monte Carlo codedevelopment and application on the formation of hydrogen-vacancy clusters in tungsten

Meng, Chao; Hao, Jiannan; Xu, Ke; Wang, Lifang; Shu, Xiang; Jin, Shuo; Lü, Guang-Hong

doi:10.1007/s11433-018-9253-2

Cited by 3 publications

(3 citation statements)

References 28 publications

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“…Considering the different available volume and the electronic environment, the behavior of H in large VCs is significantly different from that in a mono-/di-vacancy. To address this issue, great effort has been made by employing large-scale simulations, such as molecular dynamics (MD), kinetic Monte Carlo (KMC), etc, based on the empirical interatomic potential or energetic results from DFT calculations [39,[41][42][43][44][45][46]. Although these large-scale simulations provide some useful information for the interaction of H with VCs in W, such as the binding energy of large H-V complexes and the temperature-dependent variation of cluster concentrations [39,42], these results are strongly dependent on the interatomic potential employed [47,48] and some important characteristics (such as H 2 formation that is proposed by experiments [9,17]) cannot be reproduced by MD and KMC simulations.…”

Section: Introductionmentioning

confidence: 99%

Characterization of the energetics and configurations of hydrogen in vacancy clusters in tungsten

Ren

Zhou

et al. 2019

Nucl. Fusion

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We have explored the retention of hydrogen (H) in tungsten (W) by investigating its dissolution and aggregation in vacancy clusters (VCs) using a first-principles method and thermodynamic models. The solution energy of a single H in the VCs is in the range of −0.99 to −0.64 eV, much lower than that at a mono-vacancy (~ −0.37 eV) and interstitial site (~1.01 eV) in W. Such a remarkable discrepancy is rationalized on the electronic interaction of H with its neighboring W atoms, which varies from repulsion to attraction with H moving from perfect crystal to vacancy/VCs. Specifically, the solution/trapping energies of H in VCs can be well categorized by the coordination number of its neighboring W atoms, i.e. the lower the coordination number of W, the stronger the H-W attraction and the lower the H solution/ trapping energy. Furthermore, taking the V m 9 cluster as an example, it is observed that the multiple H atoms form a multilayer nested cage configuration at the VC surface initially, and then the stable H 2 molecules form in the center of the VCs. Interestingly, the pre-existing H atoms in the VC inner surface have a shielding effect on the H-W interaction, decreasing the electron density of the central region of the VCs and facilitating the formation of H 2 molecules. Moreover, the desorption temperatures of H in the VCs are also predicted based on the Polanyi-Wigner equation, and are in good agreement with the available thermal desorption spectroscopy experiments. Our calculations provide a good reference to understand the influence of VCs on the retention and evolution of H in W.

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Section: Introductionmentioning

confidence: 99%

Characterization of the energetics and configurations of hydrogen in vacancy clusters in tungsten

Ren

Zhou

et al. 2019

Nucl. Fusion

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“…The transmuted Re atoms also affect the dislocation loops greatly through a complicated transmutation-diffusion-segregation mechanism [17]. Meng et al [18] studied the clustering behaviour of H with monovacancies using their own OKMC code, and the temperature dependence of dominating H m V 1 clusters was obtained. As shown above, although some work on the clustering of H with V has already been done, the temperature-dependent clustering behaviour of H and large V clusters for a long-time evolution in W remains unclear.…”

Section: Introductionmentioning

confidence: 99%

“…In this work, we systematically investigate the clustering behaviour of H with V clusters in W using the OKMC method and our own code, which has been previously validated by studying the behavior of H clustering with monovacancies [18]. We should mention that SIAs are not considered in the simulation although SIAs and vacancies are generated as Frankel pairs after a cascade during the irradiation.…”

Section: Introductionmentioning

confidence: 99%

Object Kinetic Monte Carlo simulation of hydrogen clustering behaviour with vacancies in tungsten

Meng

Wang

et al. 2019

Journal of Nuclear Materials

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We apply the Object Kinetic Monte Carlo method to simulate the hydrogen (H) clustering behaviour with large vacancy (V) clusters in tungsten. The main advantage of this method is to consider the temperature effects, large V clusters, and long-time evolution. It is thus a very useful tool to study the microstructure evolution of defects in irradiated materials covering from atomic scale to mesoscale. Simulation results show that the number of trapped H atoms by V and V clusters decreases with the increase of temperature. This is expected, because the de-trapping ability of H atoms increases when the temperature is increased. With the correction of the zero-point-energy in calculating binding energies, the present results show that the number of H atoms trapped by monovacancy decreases for all studied temperatures. We also found that the trapping ability of V clusters for H decreases with the increase of the sizes of V clusters, independent on temperature. The H concentration can largely affect the clustering behaviour of H m V n. When the H saturation concentration is reached, the clustering behaviour of H m V n is mainly determined by the sizes of V clusters.

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High-entropy alloy and amorphous alloy composites fabricated by ultrasonic vibrations

Liang

Zhu

et al. 2020

Sci. China Phys. Mech. Astron.

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Kinetic Monte Carlo codedevelopment and application on the formation of hydrogen-vacancy clusters in tungsten

Cited by 3 publications

References 28 publications

Characterization of the energetics and configurations of hydrogen in vacancy clusters in tungsten

Characterization of the energetics and configurations of hydrogen in vacancy clusters in tungsten

Object Kinetic Monte Carlo simulation of hydrogen clustering behaviour with vacancies in tungsten

High-entropy alloy and amorphous alloy composites fabricated by ultrasonic vibrations

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