Characterisation of helium ion irradiated bulk tungsten: A comparison with the in-situ TEM technique

R. W. Harrison, N. Peng, R. P. Webb, J. A. Hinks, S. E. Donnelly

Research output: Contribution to journalArticle

Abstract

Transmission electron microscopy (TEM) of ex-situ He ion irradiated bulk W has been performed to quantitatively compare the damage microstructure to that observed in regions of comparable thicknesses during in-situ ion irradiation with TEM experiments. Samples were irradiated to achieve He-appm/DPA ratios of 2000 and 500 at temperatures of 500 and 800 °C to 1.5 and 3.0 DPA. For irradiations at 500 °C, bubble diameters (∼2 nm) were larger and areal bubble densities (∼1012 bubbles/cm2) were lower than those in the in-situ experiments. This is attributed to greater amounts of He being retained in the ex-situ bulk experiments whereas in the in-situ experiments some may escape due to the proximity of surfaces. Dislocation loops were observed in all samples and were characterised as b = ±½<111> type with no b = <100> type loops. Dislocation loop populations were dominated by interstitial type (∼60%) agreeing with in-situ experiments. However, dislocation loops in this work were larger, ranging in size from 7 to 100 nm and large concentrations of entangled dislocation lines were observed in the bulk of the grain as compared to in the in-situ experiments.

LanguageEnglish
Pages210-216
Number of pages7
JournalFusion Engineering and Design
Volume138
Early online date28 Nov 2018
DOIs
Publication statusPublished - 1 Jan 2019

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Helium
Tungsten
Ions
Transmission electron microscopy
Experiments
Ion bombardment
Irradiation
Microstructure

Cite this

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title = "Characterisation of helium ion irradiated bulk tungsten: A comparison with the in-situ TEM technique",
abstract = "Transmission electron microscopy (TEM) of ex-situ He ion irradiated bulk W has been performed to quantitatively compare the damage microstructure to that observed in regions of comparable thicknesses during in-situ ion irradiation with TEM experiments. Samples were irradiated to achieve He-appm/DPA ratios of 2000 and 500 at temperatures of 500 and 800 °C to 1.5 and 3.0 DPA. For irradiations at 500 °C, bubble diameters (∼2 nm) were larger and areal bubble densities (∼1012 bubbles/cm2) were lower than those in the in-situ experiments. This is attributed to greater amounts of He being retained in the ex-situ bulk experiments whereas in the in-situ experiments some may escape due to the proximity of surfaces. Dislocation loops were observed in all samples and were characterised as b = ±½<111> type with no b = <100> type loops. Dislocation loop populations were dominated by interstitial type (∼60{\%}) agreeing with in-situ experiments. However, dislocation loops in this work were larger, ranging in size from 7 to 100 nm and large concentrations of entangled dislocation lines were observed in the bulk of the grain as compared to in the in-situ experiments.",
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Characterisation of helium ion irradiated bulk tungsten : A comparison with the in-situ TEM technique. / Harrison, R. W.; Peng, N.; Webb, R. P.; Hinks, J. A.; Donnelly, S. E.

In: Fusion Engineering and Design, Vol. 138, 01.01.2019, p. 210-216.

Research output: Contribution to journalArticle

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