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Talks and Poster Presentations (without Proceedings-Entry):

M. Schöbel, H.P. Degischer, G. Fiedler, W. Altendorfer:
"Residual stresses and their effects on thermal fatigue in monofilament reinforced composites for heat sink applications in novel fusion reactor systems";
Poster: NRJ Konference Pettenn NL, Petten; 04-16-2008 - 04-18-2008.



English abstract:
Monofilament reinforced metal matrix composites are used in divertor elements for fusion reactors. The divertor collects the residues of the nuclear reaction out from the plasma and transports the heat into the cooling medium. For this purpose a plasma facing material capable to survive high temperatures has to be connected to a water cooled heat sink material with a good thermal conductivity. Copper is used as heat sink and has to be attached to a tungsten component which is exposed to the hot reaction chamber. A metal matrix composite is developed as interconnection between these different materials to avoid debonding caused by thermal expansion mismatch at the interface. This MMC must combine good thermal conductivity with a low thermal expansion. Copper matrix composites reinforced with monofilaments were developed in this work. Investigations on different fiber coatings and fiber materials show their capability for application in divertor elements. The thermal expansion mismatch between the metal matrix and the reinforcements lead to residual stresses causing debonding, fiber fracture and matrix deformation. These stresses were evaluated by neutron diffraction during thermal cycling. The effect of thermal expansion mismatch and interface quality on the long term stability were also investigated. The residual stresses built up during thermal cycling show matrix deformation, fiber fracture or debonding and thermal fatigue after multiple cycles.

Keywords:
MFRM, heat sink, neutron diffraction, thermal fatigue

Created from the Publication Database of the Vienna University of Technology.