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- Consolidation of W–Ta composites: hot isostatic pressing and spark and pulse plasma sinteringPublication . Dias, Marta; Guerreiro, F.; Correia, J.B.; Galatanu, Andrei; Rosinski, M.; Monge, M. A.; Munoz, A.; Alves, E.; Almeida Carvalho, PatriciaComposites consisting of tantalum fiber/powder dispersed in a nanostructured W matrix have been consolidated by spark and pulse plasma sintering as well as by hot isostatic pressing. The microstructural observations revealed that the tungsten–tantalum fiber composites consolidated by hot isostatic pressing and pulse plasma sintering presented a continuous layer of Ta2O5 phase at the W/Ta interfaces, while the samples consolidated by spark plasma sintering evidenced a Ta + Ta2O5 eutectic mixture due to the higher temperature of this consolidation process. Similar results have been obtained for the tungsten–tantalum powder composites. A (W, Ta) solid solution was detected around the prior nanostructured W particles in tungsten–tantalum powder composites consolidated by spark and pulse plasma sintering. Higher densifications were obtained for composites consolidated by hot isostatic pressing and pulse plasma sintering.
- Effects of helium and deuterium irradiation on SPS sintered W–Ta composites at different temperaturesPublication . Mateus, R.; Dias, Marta; Lopes, J.; Rocha, J.; Catarino, N.; Franco, N.; Livramento, Vanessa; Almeida Carvalho, Patricia; Correia, J.B.; 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.% Ta were prepared from elemental W powder and Ta fibre or powder through low-energy ball milling in argon atmosphere. Spark plasma sintering (SPS) was used as the consolidation process in the temperature range from 1473 to 1873 K. The results obtained from pure elemental samples and composites are similar. However, Ta2H is easily formed in pure Ta by using a pre-implantation stage of He+, whereas in W–Ta composites the same reaction is clearly reduced, and it can be inhibited by controlling the sintering temperature.