Response of unalloyed tungsten to mixed spectrum neutrons

Katoh, Yutai; Snead, Lance Lewis; Garrison, Lauren M.; Hu, Xunxiang; Koyanagi, Takaaki; Parish, Chad M.; Edmondson, Philip D.; Fukuda, Makoto; Hwang, Taeyon; Tanaka, Teruya; Hasegawa, Akira

doi:10.1016/j.jnucmat.2019.03.045

Cited by 82 publications

(42 citation statements)

References 74 publications

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“…They attributed this behavior to the dislocation loops originating from collision cascades, which act as trap for diffusing Os and Re atoms thereby seeding the precipitates. In contrast to Katoh et al 35 we found that both types of precipitates (σ-and the χ-type) are present within our sample. We found that out-of-plane the σ-phase [110] axis is oriented along the [110] of W, whereas in-plane the orientation relation is (1-10)W || (1-12)σ and (002)W || (-441)σ.…”

Section: Discussioncontrasting

confidence: 99%

“…larger than 1 10 23 m -3 , only occur for irradiation temperatures below 760°C at low doses 25 . The results summarized from different publications exhibit the tendency that the average void size increases from 4 nm to 7 nm and decrease in number density for doses exceeding 1.0 dpa, while the temperature influence on both parameters is statistically insignificant 35 . The voids formed at similar conditions (Tirr = 900°C, 1.54 dpa) are considerably smaller in size and have an order of magnitude higher number density than the voids reported in current work 6 .…”

Section: Discussionmentioning

confidence: 95%

“…Figure 4). Recently formation of clouds with a diameter of about ∼30 nm has been reported in several publications 3,5,6,35,40 . The value is twice as small as the average diameter of 60-80 nm measured in our work.…”

Section: Discussionmentioning

confidence: 97%

“…The crystallographic structure of the intragranular precipitates is still under debate at present time. On the one hand, Katoh et al 35 claim that the platelet-shaped precipitates found in samples irradiated at elevated temperatures and doses around one dpa are inconsistent with the σ-and the χ-type phase.…”

Section: Discussionmentioning

confidence: 99%

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New microstructural insights into neutron-irradiated tungsten

Dürrschnabel¹,

Klimenkov²,

Jäntsch³

et al. 2020

Preprint

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The development of appropriate materials for fusion reactors that can sustain high neutron fluencies at elevated temperatures remains a great challenge. Tungsten is one of the promising candidate materials for plasma-facing components of future fusion reactors, due to several favorable properties as for example a high melting point, a high sputtering resistivity, and a low coefficient of thermal expansion. The microstructural details of a tungsten sample with a 1.25 dpa (displacements per atom) damage dose after irradiation at 800°C were examined by transmission electron microscopy (TEM). Three types of radiation-induced defects were observed, analyzed and characterized: (i) voids with sizes ranging from 10 nm to 65 nm, (ii) dislocation loops with a size of up to 10 nm and (iii) W-Re-Os containing σ- and χ-type precipitates. The distribution of voids as well as the nature of the occurring dislocation loops were studied in detail. In addition, nano-chemical analyses revealed that the σ- and χ-type precipitates, which are sometimes attached to voids, are surrounded by a solid solution cloud enriched with Re. For the first time the crystallographic orientation relationship of the σ- and χ-phases to the W-matrix was specified. Furthermore, electron energy-loss spectroscopy could not unambiguously verify the presence of He within individual cavities.

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Section: Discussioncontrasting

confidence: 99%

Section: Discussionmentioning

confidence: 95%

Section: Discussionmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 99%

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New microstructural insights into neutron-irradiated tungsten

Dürrschnabel¹,

Klimenkov²,

Jäntsch³

et al. 2020

Preprint

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“…Fusion energy applications require materials to possess superior properties able to withstand extreme environments of high thermal loads, transient heat fluxes, high fluxes of helium (He) plasma particles, and fast neutrons [1]. Furthermore, neutron irradiation can also lead to solid transmutation products and He gas formation [2]. These challenging conditions can exacerbate damage in materials facing the plasma.…”

Section: Introductionmentioning

confidence: 99%

In-Situ Helium Implantation and TEM Investigation of Radiation Tolerance to Helium Bubble Damage in Equiaxed Nanocrystalline Tungsten and Ultrafine Tungsten-TiC Alloy

et al. 2020

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The use of ultrafine and nanocrystalline materials is a proposed pathway to mitigate irradiation damage in nuclear fusion components. Here, we examine the radiation tolerance of helium bubble formation in 85 nm (average grain size) nanocrystalline-equiaxed-grained tungsten and an ultrafine tungsten-TiC alloy under extreme low energy helium implantation at 1223 K via in-situ transmission electron microscope (TEM). Helium bubble damage evolution in terms of number density, size, and total volume contribution to grain matrices has been determined as a function of He + implantation fluence. The outputs were compared to previously published results on severe plastically deformed (SPD) tungsten implanted under the same conditions. Large helium bubbles were formed on the grain boundaries and helium bubble damage evolution profiles are shown to differ among the different materials with less overall damage in the nanocrystalline tungsten. Compared to previous works, the results in this work indicate that the nanocrystalline tungsten should possess a fuzz formation threshold more than one order of magnitude higher than coarse-grained tungsten.

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