V. Paffenholz, S. Lindig, A. Brendel, H. Bolt

Copper matrix composites reinforced with silicon carbide (SiC) fibres are a promising candidate material for the heat sink of future fusion reactors as they combine high thermal conductivity and high mechanical strength at elevated temperatures.
The fusion plasma leads to a heat flux of up to 20 MW/m² in the divertor region of the reactor vessel. The heat has to be removed from the plasma facing component (PFM) through the Cu based heat sink material to the cooling channel. For efficient energy production a coolant temperature of 300°C is necessary, which leads to temperatures of up to 550°C at the interface between the PFM (W) and the heat sink material (CuCrZr). This interface should be strengthened by a Cu matrix reinforced with silicon carbide (SiC) fibres.
SiCf-Cu composite specimens consisting of 3 and 5 unidirectional (UD) layers were processed to investigate the thermal conductivity perpendicular to the fibre direction by LFA (laser flash apparatus) measurements. The UD-layers, prepared by two subsequent electroplating processes, were stacked with different fibre volume fraction and different relative fibre orientations and consolidated by vacuum hot pressing to form the MMC specimens. Preliminary results of selected MMC specimens showed thermal conductivities well above the required value of 200 Wm-1K-1. The combination of optimal fibre volume fraction and fibre orientation will be unified in an optimised mock-up for heat flux experiments to analyse the thermal performance of the whole component.

Heat flux tests of SiC-fibre

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