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

7 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

Keywords

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

Fingerprint Dive into the research topics of 'Helium and deuterium irradiation effects in W-Ta composites produced by pulse plasma compaction'. Together they form a unique fingerprint.

  • Cite this