A. Brendel (Sp), T. Koeck, H. Bolt, Max Planck Institute for Plasma Physics, Garching (Germany); T.
Brendel, MTU Aero Engines, München (Germany)
The divertor is one of the highest loaded zones (up to 15 MW/m²) in a fusion reactor. Therefore the plasma facing
material (PFM) in the divertor region needs an effective heat sink with cooling channels to remove the heat
coming from the fusion plasma.
Future fusion reactors like DEMO will operate with cooling temperatures of at least 300°C for efficient energy
production. This will lead to temperatures of up to 550°C at the interface between PFM (W, C) and heat sink
material (CuCrZr). To strengthen this zone a metal matrix composite is suggested consisting of SiC fibre
reinforced copper. The fibres will contribute the strength of the composite and the copper provides the required
thermal conductivity of at least 200 W/mK.
SiC fibres (SCS 6, Specialty Materials) were coated with a 100 nm thick titanium interlayer by magnetron
sputtering and subsequently galvanically coated with copper as matrix material. The thickness of the copper
coating defines the fibre volume fraction. The coated single fibres were packed into a copper capsule and hot
isostatically pressed at 650°C and 100 MPa to form the composite. The tensile strength of the composite in
dependence on the fibre volume fraction was determined with tensile tests at room temperature as well as at
550°C. For a composite with a fibre volume fraction of 10% a tensile strength of 210 MPa at room temperature
was determined. A composite with 17% fibre volume fraction has a tensile strength of 100 MPa and a Young's
modulus of 112 GPa at 550°C.