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Elemental interdiffusion in W-Ta composites developed for fusion applications
Mateus, R.; Dias, M.; Livramento, Vanessa; Nunes, D.; Carvalho, P. A.; Hanada, K.; Correia, J. BritoTungsten (W) was select for an extensive use in nuclear fusion devices due to its low neutron activation, high melting point and sputtering threshold as well as low hydrogen inventory. Nevertheless, W is brittle at low and moderate temperatures, which results in abnormal thermal stress, component fracture and extra erosion under reactor operation due to inherent thermal cycling events. An attractive way to solv...
Blistering of W–Ta composites at different irradiation energies
Mateus, R.; Dias, M.; Lopes, J.; Rocha, J.; Catarino, N.; Duarte, P.; Gomes, R. B.; Silva, C.; Fernandes, H.; Livramento, Vanessa; Carvalho, P. A.Pure tungsten and tantalum plates and tungsten–tantalum composites produced via mechanical alloying and spark plasma sintering were bombarded with He+ and D+ energetic ion beams and deuterium plasmas. The aim of this experiment is to study the effects caused by individual helium and deuterium exposures and to evidence that the modifications induced in the composites at different irradiation energies could be fo...
Synergistic helium and deuterium blistering in tungsten–tantalum composites
Dias, M.; Mateus, R.; Catarino, N.; Franco, N.; Nunes, D.; Correia, J. Brito; Carvalho, P. A.; Hanada, K.; Sârbu, C.; Alves, E.Tungsten–tantalum composites with 10 and 20 at.% Ta were prepared by ball milling W powder with Ta fibers and by consolidating the milled materials with spark plasma sintering. The composites were implanted at room temperature with He+ (30 keV with a fluence 5 1021 at/m2) and/or D+ (15 keV with a fluence 5 x 1021 at/m2) ion beams. The materials were studied by scanning and high-resolution transmission electron ...
Effects of helium and deuterium irradiation on SPS sintered W–Ta composites at ...
Mateus, R.; Dias, M.; Lopes, J.; Rocha, J.; Catarino, N.; Franco, N.; Livramento, Vanessa; Carvalho, P. A.; Correia, J. Brito; Hanada, K.; Alves, E.Energetic He+ and D+ ions were implanted into different W–Ta composites in order to investigate their stability under helium and deuterium irradiation. The results were compared with morphological and chemical modifications arising from exposure of pure W and Ta. Special attention was given to tantalum hydride (Ta2H)formation due to its implications for tritium inventory. Three W–Ta composites with 10 and 20 at...
Production of Cu/Diamond composites for first-wall heat sinks
Nunes, D.; Correia, J. Brito; Carvalho, P. A.; Shohoji, Nobumitsu; Silva, C.; Fernandes, H.; Alves, L. C.; Hanada, K.; Osawa, E.Due to their suitable thermal conductivity and strength copper-based materials have been considered appropriate heat sinks for first wall panels in nuclear fusion devices. However, increased thermal conductivity and mechanical strength are demanded and the concept of property tailoring involved in the design of metal matrix composites advocates for the potential of nanodiamond dispersions in copper. Copper-nano...
Novel approach to plasma facing materials in nuclear fusion reactors
Livramento, Vanessa; Correia, J. Brito; Nunes, D.; Carvalho, P. A.; Fernandes, H.; Silva, C.; Hanada, K.; Shohoji, Nobumitsu; Osawa, E.A novel material design in nuclear fusion reactors is proposed based on W-nDiamond nanostructured composites. Generally, a microstructure refined to the nanometer scale improves the mechanical strength due to modification of plasticity mechanisms. Moreover, highly specific grainboundary area raises the number of sites for annihilation of radiation induced defects. However, the low thermal stability of fine-grai...
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