Book/Report

FZJ-2018-04053

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Zur Bestimmung der Belastungsgrenzen verschiedener nichtmetallischer Materialien mittels Laserbestrahlung unterschiedlicher Leistungsdichte und Pulsdauer

Benz, A. (Corresponding author)FZJ* ; Naoumidis, A.FZJ* ; Nickel, H.FZJ*

1992
Forschungszentrum Jülich GmbH Zentralbibliothek Verlag Jülich

Please use a persistent id in citations: http://hdl.handle.net/2128/19274

Report No.: Juel-2702

Abstract: For the selection of materials for plasma facing components (PFC) in future nuclear fusion devices subjected to short-time high heat fluxes it is desireable to determine the threshold values of the occuring damages in laboratory experiments. In order to determine the response of candidate materials to thermal shock-loading different nonmetallic materials were exposed to the beam of a 10 kW NdYAG solid state laser situated in the Institute für Lasertechnik under the Fraunhofer Gesellschaft in Aachen. The impinging power density was variied between 200 and 2000 MW/m$^{2}$ for pulse lengths t$_{p}$ ranging from 0.1 to 10ms. Similar conditions are expected to occur under plasma disruptions in Tokamak fusion devices. The absorbed power density $\Phi_{abs}$ was determined by measuring reflexion losses from the sample surfaces. The main damages on nitride and carbide ceramics were cracking and chemical decomposition. Sublimation was the main structural change observed on all carbon materials though cracking could be detected in pyrolytic grafite and melting in a coatmix material. Two coated materials showed cracking and melting of the coating layer. The threshold values for these structural damages were quantified by using a heat flux parameter $\Phi_{abs} \surd t_{p}$. Parallel to these experiments numerical calculations were carried out. The calculated threshold values are in approximate agreement with the experimental results. Other heat tests on selected carbon materials were carried out to establish a comparison between electron beam and laser beam erosion under nearly equal conditions. Theresults are in a good qualitative accordance. It can be concluded that laser beam testing presents a simple methode to rate materials according to their behavior under thermal shock conditions.

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Contributing Institute(s):

1. Publikationen vor 2000 (PRE-2000)

Research Program(s):

1. 899 - ohne Topic (POF3-899) (POF3-899)

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Database coverage:

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