Novel approach to plasma facing materials in nuclear fusion reactors

• Autor(es): Livramento, Vanessa ; Correia, J. Brito ; Nunes, D. ; Carvalho, P. A. ; Fernandes, H. ; Silva, C. ; Hanada, K. ; Shohoji, Nobumitsu ; Osawa, E.
• Data: 2008
• Identificador Persistente: http://hdl.handle.net/10400.9/727
• Origem: Repositório do LNEG
• Assunto(s): Mechanical alloying; Nanoparticles; Composite materials
• Tipo de Documento: Documento de conferência
• Idioma: Inglês

Descrição

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-grained and nanostructured materials demands the presence of particles at the grain boundaries that can delay coarsening by a pinning effect. As a result, the concept of a composite is promising in the field of nanostructured materials. The hardness of diamond renders nanodiamond dispersions excellent reinforcing and stabilization candidates and, in addition, diamond has extremely high thermal conductivity. Consequently, W-nDiamond nanocomposites are promising candidates for thermally stable first-wall materials. The proposed design involves the production of WAV-nDiamondAV-Cu/Cu layered castellations. The W, W-nDiamond and W-Cu layers are produced by mechanical alloying followed by a consolidation route that combines hot rolling with spark plasma sintering (SPS). Layer welding is achieved by spark plasma sintering. The present work describes the mechanical alloying processsing and consolidation route used to produce W-nDiamond composites, as well as microstructural features and mechanical properties of the material produced Long term plasma exposure experiments are planned at ISTTOK and at FTU (Frascati).