Effect of 800 keV argon ions pre-damage on the helium blister formation of tungsten exposed to 60 keV helium ions

Chen, Zhe; Han, Wenjia; Yu, Jiangang; Zhu, Kaigui

doi:10.1016/j.jnucmat.2016.01.031

Cited by 37 publications

(15 citation statements)

References 50 publications

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“…Previous results showed that blistering of the W surface had significant grain orientation dependence when exposed to low energy, high flux D plasmas, where grains with normal directions close to the [001] direction exhibited better blistering behavior than others [41][42][43][44]. The results of section 3.3 showed that surface modification and plastic deformation of the W surface also has grain orientation dependence under steady-state and transient heat flux loading.…”

Section: Discussionmentioning

confidence: 89%

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Recent progress of thick tungsten coating prepared by chemical vapor deposition as the plasma-facing material

Chen¹,

Li²,

Cheng³

et al. 2021

Nucl. Fusion

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Chemical vapor deposition (CVD) is a promising technique for the preparation of Wbased plasma-facing materials (PFMs). An overview of the microstructure, chemical composition, thermal conductivity, thermal stability, thermal shock performance under disruption-like and edge localized mode (ELM)-like transient heat load, and neutron irradiation performance of CVD-W has been given in our previous work. However, for fusion applications, additional properties need to be assessed. To this end, deuterium (D) permeability, D plasma irradiation performance, and thermal fatigue resistance of CVD-W were investigated in this work. The results showed that the D permeability of CVD-W in the temperature range of 973-1173 K was larger than that of the commercial pure W, which was related to the columnar grain structure of CVD-W. Additionally, both CVD-W and commercial pure W were exposed to D plasma up to a fluence of 1 × 10 26 m -2 . Compared to commercial pure W, CVD-W exhibited a mitigated blistering behavior and lower D total retention, which could be attributed to its strong [001] crystallographic texture along the thickness direction and a lower number of defect density (e.g. grain boundaries). CVD-W and commercial pure W were also exposed to steady-state and transient heat load simultaneously, leading to a base surface temperature and surface temperature increase of about 953-1473 K and 250-300 K, respectively. A strong grain orientation dependence of the surface degradation induced by the combined heat load has been found. Consequently, CVD-W exhibited a much more uniform plastic deformation than pure W, and no surface cracks along grain boundaries were observed in CVD-W. Finally, the industrial-scale production of CVD-W-based PFMs and mockups was demonstrated. This work paves the way for the fusion applications of thick CVD-W coatings.

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Section: Discussionmentioning

confidence: 89%

“…Ref. [41][42][43][44]), it is safe to state that the non-uniform distribution of blisters was due to the difference in grain orientation.…”

Section: Blistering and Retentionmentioning

confidence: 99%

Recent progress of thick tungsten coating prepared by chemical vapor deposition as the plasma-facing material

Chen¹,

Li²,

Cheng³

et al. 2021

Nucl. Fusion

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“…Helium retentions counted by integrating TDS spectra of helium of W and W-5%Cr are 3.24 × 10 16 and 1.78 × 10 16 ion•m −2 , respectively. For pure W, there is a shoulder at about 500 K. Lee et al [17,26,27] have shown that the low temperature desorption peak of helium is at 550 K. The different temperature ramping rates that are used would lead to its variation, where 2.7-3.2 K/s was used by Lee et al but 1 K/s is used in this work. According to their research, the 500 K desorption peak may from the release of helium atoms trapped at grain boundaries, internal defects in the crystal or dislocation loops near He 𝑛 V 𝑚 complexes.…”

Section: -3mentioning

confidence: 97%

Blistering and Helium Retention of Tungsten and 5% Chromium Doped Tungsten Exposed to 60 keV Helium Ions Irradiation

Lv¹,

Han²,

Yu³

et al. 2018

Chinese Phys. Lett.

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Pure tungsten (W) and chromium doped W (W-5%Cr) are prepared by powder metallurgy. The microstructure, blistering and helium retention are investigated by x-ray diffraction, scanning electron microscopy, transmission electron microscopy and thermal desorption spectroscopy (TDS). These results show that the average size and density of helium blisters on the surface of pure W are much larger than those on the W-5%Cr alloy. Vacancyimpurity pairs can reduce the migration coefficients of vacancy and vacancy-helium complexes, and Cr may play a role of such an impurity. Moreover, the TDS result shows that the highest desorption peak moves to higher temperature, which is attributed to the He𝑚Cr 𝑘 V𝑛 complexes in the W-Cr alloy. In addition, the helium retention is found to be higher in W than in W-5%Cr.

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“…Despite the importance of the material, few experimental studies have considered its use in radiation environments, − and even fewer irradiation experiments have been performed, chiefly in the 1970s with the aim of hardening the material for cutting tools. − This is in contrast to W metal, in which the microstructural evolution under irradiation, and the corresponding changes in material properties, have been extensively characterized through experimental irradiation with He, − H isotopes, − heavy ions, ,− and neutrons. − A particular concern of W (both alloyed and unalloyed), is the segregation of Re and Os transmutation products, first in the form of clusters within the W matrix and later as Re–Os-rich precipitates, ,, which are known to aggravate the radiation-induced embrittlement of W metal. , The fluence at which these precipitates appear, and when they start to dominate the degradation of the mechanical properties, is dependent on alloy type, temperature, and neutron flux. , …”

Section: Introductionmentioning

confidence: 99%

Radiation-Induced Evolution of Tungsten Carbide in Fusion Reactors: Accommodation of Defect Clusters and Transmutation Elements

Oliver

Jackson

Burr

2019

ACS Appl. Energy Mater.

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The development of suitable shielding material is a key challenge in the advancement of spherical tokamak fusion reactors. Tungsten carbide (WC) is a promising candidate material owing to its low neutron and gamma attenuation lengths resulting from the combination of high-Z and low-Z elements, but its behavior under prolonged exposure to fusion neutrons is poorly understood. Here, we shed light on the microstructural evolution of WC under neutron irradiation by investigating the formation and clustering of defects using density functional theory atomic simulations. It is found that deviation from stoichiometry is accommodated entirely by C defects (vacancies and interstitials), while the disorder induced by radiation damage may be accommodated by three competing processes (C- Frenkel, antisite, and Schottky) with similar energetics. Vacancy clusters involving a combination of both tungsten and carbon vacancies show increasingly favorable binding energies with increasing cluster size and may lead to the formation of undesirable extended defects such as dislocation loops and voids. The accommodation of the three main transmutation elements Re, Os, and Ta was also considered, as well as their interaction with radiation-induced intrinsic defects. It was found that all three species are preferentially accommodated as substitution defects on the W sublattice, and they all exhibit a thermodynamic drive to bind with W vacancies, while Ta also binds with C vacancies and with Re and Os substitutions. This suggests that radiation-induced vacancy sinks (e.g., voids and dislocation loops) will likely be enriched in transmutation elements, and that these further stabilize the vacancy clusters, potentially aggravating swelling. However, it is predicted that under equilibrium conditions, all three species exhibit limited solubility in WC, assuming that the competing phases for precipitation are TaC(s), Os(s), and Re(s). Further investigation into the C-(Ta,Re,Os)-W phase diagram is needed to improve the accuracy of these predictions.

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Effect of 800 keV argon ions pre-damage on the helium blister formation of tungsten exposed to 60 keV helium ions

Cited by 37 publications

References 50 publications

Recent progress of thick tungsten coating prepared by chemical vapor deposition as the plasma-facing material

Recent progress of thick tungsten coating prepared by chemical vapor deposition as the plasma-facing material

Blistering and Helium Retention of Tungsten and 5% Chromium Doped Tungsten Exposed to 60 keV Helium Ions Irradiation

Radiation-Induced Evolution of Tungsten Carbide in Fusion Reactors: Accommodation of Defect Clusters and Transmutation Elements

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