Helium and deuterium irradiation effects in W-Ta composites produced by pulse plasma compaction

M. Dias, N. Catarino, D. Nunes, E. Fortunato, I. Nogueira, M. Rosinki, J. B. Correia, P. A. Carvalho, E. Alves

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Tungsten-tantalum composites have been envisaged for first-wall components of nuclear fusion reactors; however, changes in their microstructure are expected from severe irradiation with helium and hydrogenic plasma species. In this study, composites were produced from ball milled W powder mixed with 10 at.% Ta fibers through consolidation by pulse plasma compaction. Implantation was carried out at room temperature with He+ (30 keV) or D+ (15 keV) or sequentially with He+ and D+ using ion beams with fluences of 5 × 1021 at/m2. Microstructural changes and deuterium retention in the implanted composites were investigated by scanning electron microscopy, coupled with focused ion beam and energy dispersive X-ray spectroscopy, transmission electron microscopy, X-ray diffraction, Rutherford backscattering spectrometry and nuclear reaction analysis. The composite materials consisted of Ta fibers dispersed in a nanostructured W matrix, with Ta2O5 layers at the interfacial regions. The Ta and Ta2O5 surfaces exhibited blisters after He+ implantation and subsequent D+ implantation worsened the blistering behavior of Ta2O5. Swelling was also pronounced in Ta2O5 where large blisters exhibited an internal nanometer-sized fuzz structure. Transmission electron microscopy revealed an extensive presence of dislocations in the metallic phases after the sequential implantation, while a relatively low density of defects was detected in Ta2O5. This behavior may be partially justified by a shielding effect from the blisters and fuzz structure developed progressively during implantation. The tungsten peaks in the X-ray diffractograms were markedly shifted after He+ implantation, and even more so after the sequential implantation, which is in agreement with the increased D retention inferred from nuclear reaction analysis.

Original languageEnglish
Pages (from-to)105-112
Number of pages8
JournalJournal of Nuclear Materials
Volume492
DOIs
Publication statusPublished - 15 Aug 2017

Fingerprint

Helium
Deuterium
deuterium
implantation
Compaction
helium
Irradiation
Plasmas
Tungsten
irradiation
composite materials
Nuclear reactions
blisters
Composite materials
pulses
Tantalum
Transmission electron microscopy
Fibers
Focused ion beams
Fusion reactors

Keywords

  • Blistering
  • Deuterium implantation
  • Fuzz
  • Helium implantation
  • Mechanical alloying
  • Tungsten-tantalum fiber composites

Cite this

Dias, M. ; Catarino, N. ; Nunes, D. ; Fortunato, E. ; Nogueira, I. ; Rosinki, M. ; Correia, J. B. ; Carvalho, P. A. ; Alves, E. / Helium and deuterium irradiation effects in W-Ta composites produced by pulse plasma compaction. In: Journal of Nuclear Materials. 2017 ; Vol. 492. pp. 105-112.
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abstract = "Tungsten-tantalum composites have been envisaged for first-wall components of nuclear fusion reactors; however, changes in their microstructure are expected from severe irradiation with helium and hydrogenic plasma species. In this study, composites were produced from ball milled W powder mixed with 10 at.{\%} Ta fibers through consolidation by pulse plasma compaction. Implantation was carried out at room temperature with He+ (30 keV) or D+ (15 keV) or sequentially with He+ and D+ using ion beams with fluences of 5 × 1021 at/m2. Microstructural changes and deuterium retention in the implanted composites were investigated by scanning electron microscopy, coupled with focused ion beam and energy dispersive X-ray spectroscopy, transmission electron microscopy, X-ray diffraction, Rutherford backscattering spectrometry and nuclear reaction analysis. The composite materials consisted of Ta fibers dispersed in a nanostructured W matrix, with Ta2O5 layers at the interfacial regions. The Ta and Ta2O5 surfaces exhibited blisters after He+ implantation and subsequent D+ implantation worsened the blistering behavior of Ta2O5. Swelling was also pronounced in Ta2O5 where large blisters exhibited an internal nanometer-sized fuzz structure. Transmission electron microscopy revealed an extensive presence of dislocations in the metallic phases after the sequential implantation, while a relatively low density of defects was detected in Ta2O5. This behavior may be partially justified by a shielding effect from the blisters and fuzz structure developed progressively during implantation. The tungsten peaks in the X-ray diffractograms were markedly shifted after He+ implantation, and even more so after the sequential implantation, which is in agreement with the increased D retention inferred from nuclear reaction analysis.",
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note = "sem pdf conforme despacho. European Union's Horizon 2020 research and innovation program under grant agreement number 633053. IST activities also received financial support from Fundacao para a Ciencia e a Tecnologia through projects Pest-OE/SADG/LA0010/2013 and UID/CTM/50025/2013, and FEDER funds through the COMPETE 2020 Programme under the project number POCI-01-0145-FEDER-007688. The views and opinions expressed herein do not necessarily reflect those of the European Commission. Financial support was also received from the Portuguese Science and Technology Foundation under the PTDC/CTM/100163/2008 grant and the PEST-OE/CTM-UI0084/2011 contracts. M. Dias acknowledges the FCT grant SFRH/BPD/68663/2010.",
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Helium and deuterium irradiation effects in W-Ta composites produced by pulse plasma compaction. / Dias, M.; Catarino, N.; Nunes, D.; Fortunato, E.; Nogueira, I.; Rosinki, M.; Correia, J. B.; Carvalho, P. A.; Alves, E.

In: Journal of Nuclear Materials, Vol. 492, 15.08.2017, p. 105-112.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Helium and deuterium irradiation effects in W-Ta composites produced by pulse plasma compaction

AU - Dias, M.

AU - Catarino, N.

AU - Nunes, D.

AU - Fortunato, E.

AU - Nogueira, I.

AU - Rosinki, M.

AU - Correia, J. B.

AU - Carvalho, P. A.

AU - Alves, E.

N1 - sem pdf conforme despacho. European Union's Horizon 2020 research and innovation program under grant agreement number 633053. IST activities also received financial support from Fundacao para a Ciencia e a Tecnologia through projects Pest-OE/SADG/LA0010/2013 and UID/CTM/50025/2013, and FEDER funds through the COMPETE 2020 Programme under the project number POCI-01-0145-FEDER-007688. The views and opinions expressed herein do not necessarily reflect those of the European Commission. Financial support was also received from the Portuguese Science and Technology Foundation under the PTDC/CTM/100163/2008 grant and the PEST-OE/CTM-UI0084/2011 contracts. M. Dias acknowledges the FCT grant SFRH/BPD/68663/2010.

PY - 2017/8/15

Y1 - 2017/8/15

N2 - Tungsten-tantalum composites have been envisaged for first-wall components of nuclear fusion reactors; however, changes in their microstructure are expected from severe irradiation with helium and hydrogenic plasma species. In this study, composites were produced from ball milled W powder mixed with 10 at.% Ta fibers through consolidation by pulse plasma compaction. Implantation was carried out at room temperature with He+ (30 keV) or D+ (15 keV) or sequentially with He+ and D+ using ion beams with fluences of 5 × 1021 at/m2. Microstructural changes and deuterium retention in the implanted composites were investigated by scanning electron microscopy, coupled with focused ion beam and energy dispersive X-ray spectroscopy, transmission electron microscopy, X-ray diffraction, Rutherford backscattering spectrometry and nuclear reaction analysis. The composite materials consisted of Ta fibers dispersed in a nanostructured W matrix, with Ta2O5 layers at the interfacial regions. The Ta and Ta2O5 surfaces exhibited blisters after He+ implantation and subsequent D+ implantation worsened the blistering behavior of Ta2O5. Swelling was also pronounced in Ta2O5 where large blisters exhibited an internal nanometer-sized fuzz structure. Transmission electron microscopy revealed an extensive presence of dislocations in the metallic phases after the sequential implantation, while a relatively low density of defects was detected in Ta2O5. This behavior may be partially justified by a shielding effect from the blisters and fuzz structure developed progressively during implantation. The tungsten peaks in the X-ray diffractograms were markedly shifted after He+ implantation, and even more so after the sequential implantation, which is in agreement with the increased D retention inferred from nuclear reaction analysis.

AB - Tungsten-tantalum composites have been envisaged for first-wall components of nuclear fusion reactors; however, changes in their microstructure are expected from severe irradiation with helium and hydrogenic plasma species. In this study, composites were produced from ball milled W powder mixed with 10 at.% Ta fibers through consolidation by pulse plasma compaction. Implantation was carried out at room temperature with He+ (30 keV) or D+ (15 keV) or sequentially with He+ and D+ using ion beams with fluences of 5 × 1021 at/m2. Microstructural changes and deuterium retention in the implanted composites were investigated by scanning electron microscopy, coupled with focused ion beam and energy dispersive X-ray spectroscopy, transmission electron microscopy, X-ray diffraction, Rutherford backscattering spectrometry and nuclear reaction analysis. The composite materials consisted of Ta fibers dispersed in a nanostructured W matrix, with Ta2O5 layers at the interfacial regions. The Ta and Ta2O5 surfaces exhibited blisters after He+ implantation and subsequent D+ implantation worsened the blistering behavior of Ta2O5. Swelling was also pronounced in Ta2O5 where large blisters exhibited an internal nanometer-sized fuzz structure. Transmission electron microscopy revealed an extensive presence of dislocations in the metallic phases after the sequential implantation, while a relatively low density of defects was detected in Ta2O5. This behavior may be partially justified by a shielding effect from the blisters and fuzz structure developed progressively during implantation. The tungsten peaks in the X-ray diffractograms were markedly shifted after He+ implantation, and even more so after the sequential implantation, which is in agreement with the increased D retention inferred from nuclear reaction analysis.

KW - Blistering

KW - Deuterium implantation

KW - Fuzz

KW - Helium implantation

KW - Mechanical alloying

KW - Tungsten-tantalum fiber composites

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U2 - 10.1016/j.jnucmat.2017.05.007

DO - 10.1016/j.jnucmat.2017.05.007

M3 - Article

VL - 492

SP - 105

EP - 112

JO - Journal of Nuclear Materials

JF - Journal of Nuclear Materials

SN - 0022-3115

ER -