Microstructural stability of spark-plasma-sintered W f /W composite with zirconia interface coating under high-heat-flux hydrogen beam irradiation.

0483426 - ÚFP 2018 RIV NL eng J - Journal Article
Avello de Lama, M. - Balden, M. - Greuner, H. - Höschen, T. - Matějíček, Jiří - You, J.H.
Microstructural stability of spark-plasma-sintered W f /W composite with zirconia interface coating under high-heat-flux hydrogen beam irradiation.
Nuclear Materials and Energy. Roč. 13, December (2017), s. 74-80. E-ISSN 2352-1791
R&D Projects: GA ČR GB14-36566G
EU Projects: European Commission(XE) 633053 - EUROfusion
Institutional support: RVO:61389021
Keywords : tungsten-fibre/tungsten composites * plasma-facing components * spark plasma sintering
OECD category: Composites (including laminates, reinforced plastics, cermets, combined natural and synthetic fibre fabrics
https://www.sciencedirect.com/science/article/pii/S2352179117300273

Tungsten is considered as the most suitable material for the plasma-facing armour of future fusion reactors. However, in spite of many advantageous properties, pure tungsten has a major drawback, namely, brittleness at lower temperatures and embrittlement by neutron irradiation. Tungsten fibre-reinforced tungsten (W-f/W) composites are thought to be a promising candidate material for armour owing to the pseudo-toughness effect which is based on controlled cracking of coated interfaces. In this material concept, the reliability of the material during service relies on the fabrication quality as well as the stability of microstructure, particularly, of the interfacial coating under high-heat-flux loads.
In this paper, the durability and chemical stability of Wf/W composite specimens under cyclic heatflux loads up to 20 MW/m(2) (surface temperature: 1260 degrees C) was investigated using hydrogen neutral beam. The bulk material was fabricated by means of spark-plasma-sintering (SPS) method using fine tungsten powder and a stack of tungsten wire meshes as reinforcement where the surface of the wire was coated with zirconia thin film to produce an engineered interface. The impact of plasma beam irradiation on microstructure was examined for two kinds of specimens produced at different sintering temperatures, 140 0 degrees C and 170 0 degrees C. Results of microscopic (SEM) and chemical (EDX) analysis are presented comparing the microstructure and element distribution maps obtained before and after heat flux loading. Effects of different sintering temperatures on damage behaviour are discussed. The present composite materials are shown to be applicable as plasma-facing material for high-heat-flux components.
Permanent Link: http://hdl.handle.net/11104/0278746