First-principles study of Frenkel pair recombination in tungsten

Qin, Shi-Yao; Jin, Shuo; Li, Yu‐Hao; Zhou, Hongbo; Zhang, Ying; Lü, Guang-Hong

doi:10.1016/j.nimb.2016.09.032

Cited by 8 publications

(5 citation statements)

References 27 publications

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“…Such region also exists around the SIA-cluster residing within the GB [27] (Fig. 7a) or around a bulk SIA [20,24,34]. The MS calculations of the V migration kinetics near the SAR suggest that, after the SIAs are collected at the GB, the V migration energy barrier near the GB is further reduced (Fig.…”

Section: Static Interaction Of the V With Gb-trapped Sias Near The W Gbmentioning

confidence: 93%

“…Figure 1 illustrates the possible three interaction types of radiation with GBs in W (types I, II, III). Although a complete interplay picture involves the defect behavior not only near the GB [14,[17][18][19][20][21][22][23][24][25][26][27][28][29] but also in the bulk [30][31][32][33][34] or near the surface [35][36][37][38], the focus in the present paper is on the former one. Type I is relevant to defect production near the GB [14,[17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

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Interaction of radiation-induced defects with tungsten grain boundaries at across scales: a short review

Zhang

et al. 2020

Tungsten

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As promising candidates for plasma-facing materials, tungsten-based materials suffer the irradiation of high-energy neutrons in addition to the hydrogen isotopes and helium irradiation and the high-thermal flux. Radiation-produced defects, e.g. selfinterstitial atoms (SIAs) and vacancies (Vs), can induce the hardening and embrittlement of tungsten, meanwhile enhancing the retention of hydrogen isotopes and helium in tungsten. Reducing the grain size of materials to introduce a high density of defect sinks, e.g., grain boundaries (GBs) prevalent in nano-/ultrafine-crystalline materials, was demonstrated to be an effective approach for mitigating irradiation damage in tungsten. In this paper, we reviewed the theoretical advances in exploring radiation-resistance of nano-structured tungsten at across scales. It was concentrated on the results of molecular dynamics, molecular statics, and the object kinetic Monte Carlo simulations on the fundamental interaction of the radiationcreated Vs and SIAs with the GB. These mechanisms include GB-promoted V/SIA migration and SIA-V recombination, interstitial-emission induced annihilation, coupling of the V migration close to the GB with the SIA motion within the GB, and interstitial reflection by the locally dense GB structure. We proposed the remaining scientific issues on the defect-GB interactions at across scales and their relation to experimental observations. We prospected the possible trends for simulating the radiation damage accumulation and healing processes in nano-structured tungsten in terms of the development of the across-scale computational techniques and efficiency of the GB-enhanced tolerance of tungsten to irradiation under complex in-service conditions.

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Section: Static Interaction Of the V With Gb-trapped Sias Near The W Gbmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Interaction of radiation-induced defects with tungsten grain boundaries at across scales: a short review

Zhang

et al. 2020

Tungsten

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“…Therefore, a spontaneous annihilation region formed around a SIA n ('SAR' in figure 6). Such concept has been established for the V around the bulk SIA in Fe and W [25][26][27]45], which holds for the V around the bulk SIA-cluster (supplementary figure S6). Meanwhile, the annihilation mechanism could be termed as spontaneous interstitial emission ('SIE' in figure 6(c)).…”

Section: 41mentioning

confidence: 99%

“…Compared with other systems, the knowledge on the segregation and annihilation of the SIA and V in nano-crystals W is limited [24,26,29,30,33,[42][43][44][45][46][47]. Zhou et al [46,47] found that the SIA-cluster (SIA n ) in W exhibited a fast one-dimensional (1D) motion along the close packed 1 1 1 direction.…”

Section: Introductionmentioning

confidence: 99%

“…Chen et al [30] investigated the energetics of V segregation to [1 0 0] symmetric tilt GBs in W by using molecular statics. Niu et al [44] used MS method to explore the interplay between Vs, SIAs and a low-angle GB in W. Some researchers studied segregation and annihilation of the V and SIA by performing first-principles calculations [29,45]. Based on statics calculation, Li et al [24] analyzed the IE mechanism in W and its possible modification due to the extreme large binding energy of the SIA with the GB.…”

Section: Introductionmentioning

confidence: 99%

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Annihilating vacancies via dynamic reflection and emission of interstitials in nano-crystal tungsten

Duan

Zhang

et al. 2017

Nucl. Fusion

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Radiation damage not only seriously degrades the mechanical properties of tungsten (W) but also enhances hydrogen retention in the material. Introducing a large amount of defect sinks, e.g. grain boundaries (GBs) is an effective method for improving radiation-resistance of W. However, the mechanism by which the vacancies are dynamically annihilated at long timescale in nano-crystal W is still not clear. The dynamic picture for eliminating vacancies with single interstitials and small interstitial-clusters has been investigated by combining molecular dynamics, molecular statics and object Kinetic Monte Carlo methods. On one hand, the annihilation of bulk vacancies was enhanced due to the reflection of an interstitial-cluster of parallel crowdions by the GB. The interstitial-cluster was observed to be reflected back into the grain interior when approaching a locally dense GB region. Near this region, the energy landscape for the interstitial was featured by a shoulder, different to the decreasing energy landscape of the interstitial near a locally loose region as indicative of the sink role of the GB. The bulk vacancy on the reflection path was annihilated. On the other hand, the dynamic interstitial emission efficiently anneals bulk vacancies. The single interstitial trapped at the GB firstly moved along the GB quickly and clustered to be the di-interstitial therein, reducing its mobility to a value comparable to that that for bulk vacancy diffusion. Then, the bulk vacancy was recombined via the coupled motion of the di-interstitial along the GB, the diffusion of the vacancy towards the GB and the accompanying interstitial emission. These results suggest that GBs play an efficient role in improving radiation-tolerance of nano-crystal W via reflecting highly-mobile interstitials and interstitial-clusters into the bulk and annihilating bulk vacancies, and via complex coupling of in-boundary interstitial diffusion, clustering of the interstitial and vacancy diffusion in the bulk.

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The effect of hydrogen on the recombination of Frenkel pair in tungsten: A theoretical insight

Qin

Jin

Niu

et al. 2017

Sci. China Phys. Mech. Astron.

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First-principles study of Frenkel pair recombination in tungsten

Cited by 8 publications

References 27 publications

Interaction of radiation-induced defects with tungsten grain boundaries at across scales: a short review

Interaction of radiation-induced defects with tungsten grain boundaries at across scales: a short review

Annihilating vacancies via dynamic reflection and emission of interstitials in nano-crystal tungsten

The effect of hydrogen on the recombination of Frenkel pair in tungsten: A theoretical insight

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