Effect of neutron irradiation on the microstructure of tungsten

Klimenkov, M.; Jäntsch, U.; Rieth, M.; Schneider, Holger; Armstrong, David E.J.; Gibson, J. S.; Roberts, Steve

doi:10.1016/j.nme.2016.09.010

Cited by 79 publications

(67 citation statements)

References 14 publications

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“…Re clustering occurs without any assistance from RED or RIP, and hence without the need for defect sinks. This is again a remarkable feature of these alloys, confirmed in several studies [14,19,24]. As noted by Herschitz and Seidman, "The coherent precipitates were not associated with either linear or planar defects or with any impurity atoms; i.e.…”

Section: Implications Of Our Studysupporting

confidence: 71%

“…Recall from the previous section that the formation of clusters is predicated on the concerted action of both defect species, with mixed interstitials becoming trapped at small Re clusters followed by a recombination with a vacancy that makes the cluster grow over time. Clustering and precipitation of Re in irradiated W has been seen at temperatures sensibly lower than those explored here, such as 573 and 773 K for ion-irradiated W-Re [13,14,73], 773 and 1073 K for neutron irradiated W in HFIR [10], 1173 K in neutron irradiated W in the HFR reactor [19], and Williams et al at 973∼1173 K in EBR-II [22]. The work by Hasegawa et al in JOYO [9,74] does cover -by contrast-a similar temperature range as ours.…”

Section: B Brief Discussion On the Validity Of Our Resultsmentioning

confidence: 56%

“…prior to their conversion into σ and/or χ precipitates. For example, Klimenkov et al note that Re-rich particles not associated with cavities formed in neutron-irradiated single crystal W [19]. As well, using atom-probe tomography Xu et al have performed detailed analyses of Rerich atmospheres in bcc W without detecting significant numbers of vacancies [14].…”

Section: Second There Is Clear Experimental Evidence Ofmentioning

confidence: 99%

“…In spite of this, recent work using energy models based on the cluster expansion formalism for the W-Re system, and fitted to density functional theory (DFT) calculations, have revealed a direct relationship between excess vacancy concentrations and the formation of Re solute-rich clusters [18]. These calculations are substantiated by recent neutron irradiation experiments of pure W at 900 • C up to 1.6 dpa in the HFR in Petten [19]. Post-irradiation examination of the irradiated specimens reveals the formation of a fine distribution of voids with average 5 nm size surrounded by Re-rich clouds.…”

Section: Introductionmentioning

confidence: 96%

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Mechanism of nucleation and incipient growth of Re clusters in irradiated W-Re alloys from kinetic Monte Carlo simulations

et al. 2017

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7High-temperature, high-dose, neutron irradiation of W results in the formation of Re-rich clusters at concentrations one order of magnitude lower than the thermodynamic solubility limit. These clusters may eventually transform into brittle W-Re intermetallic phases, which can lead to high levels of hardening and thermal conductivity losses. Standard theories of radiation enhanced diffusion and precipitation cannot explain the formation of these precipitates and so understanding the mechanism by which nonequilibrium clusters form under irradiation is crucial to predict materials degradation and devise mitigation strategies. Here we carry out a thermodynamic study of W-Re alloys and conduct kinetic Monte Carlo simulations of Re cluster formation in irradiated W2Re alloys using a generalized Hamiltonian for crystals containing point defects parameterized entirely with electronic structure calculations. Our model incorporates recently-gained mechanistic information of mixedinterstitial solute transport, which is seen to control cluster nucleation and growth by forming quasi-spherical nuclei after an average incubation time of 13.5(±8.5) s at 1800 K. These nuclei are seen to grow by attracting more mixed interstitials bringing solute atoms, which in turns attracts vacancies leading to recombination and solute agglomeration. Owing to the arrival of both Re and W atoms from the mixed dumbbells, the clusters are not fully dense in Re, which amounts to no more than 50% of the atomic concentration of the cluster near the center. Our simulations are in qualitative agreement with recent atom probe examinations of ion irradiated W-2Re systems at 773 K.

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Section: Implications Of Our Studysupporting

confidence: 71%

Section: B Brief Discussion On the Validity Of Our Resultsmentioning

confidence: 56%

Section: Second There Is Clear Experimental Evidence Ofmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

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Mechanism of nucleation and incipient growth of Re clusters in irradiated W-Re alloys from kinetic Monte Carlo simulations

et al. 2017

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“…Recently, considerable efforts have been dedicated to micromechanical testing of small scale specimens whose microstructure can be characterized by various advanced techniques such as scanning electron microscopy [1], high resolution transmission electron microscopy [2], atom probe tomography [3], and X-ray nano-tomography [4]. This is because such small-scale tests can be ion implanted or neutron irradiated but still handled in laboratory conditions due to their small volume even if the samples show low to medium levels of activity.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of micro-scale fracture specimens for nuclear applications by direct laser writing

et al. 2018

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Manufacturing of tungsten and tungsten composites for fusion application via different routes

2019

Tungsten

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Tungsten is a refractory metal with the highest melting point of all metals, which is considered as a promising candidate material for plasma-facing materials in the future fusion reactor. However, tungsten faces several challenges from intrinsic embrittlement, irradiation embrittlement and recrystallization embrittlement during the operation of the fusion reactor. To satisfy the fusion engineering application, an advanced tungsten material with the fine grain and dense microstructure is required and developed. This paper briefly introduces the application background of the tungsten materials and mainly illustrates a series of common techniques for manufacturing advance tungsten materials, such as powder preparation technologies, bulk densification techniques, continuous processing technologies and the coating and additive manufacturing technologies. Furthermore, the development prospects for manufacturing techniques of tungsten materials are also presented in the end. Considering the tungsten materials employed in the fusion engineering application, combining these scalable techniques of the wet-chemical method, pressureless sintering and continuous deformation processing techniques would be the possible research and development routes to realize the manufacture of the advanced tungsten materials.

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Effect of neutron irradiation on the microstructure of tungsten

Cited by 79 publications

References 14 publications

Mechanism of nucleation and incipient growth of Re clusters in irradiated W-Re alloys from kinetic Monte Carlo simulations

Mechanism of nucleation and incipient growth of Re clusters in irradiated W-Re alloys from kinetic Monte Carlo simulations

Fabrication of micro-scale fracture specimens for nuclear applications by direct laser writing

Manufacturing of tungsten and tungsten composites for fusion application via different routes

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