SiC-fibre reinforced copper as heat sink material for fusion applications

The development of new heat sink materials with high thermal conductivity and sufficient strength under service loading is required for the efficiency of future fusion reactors. In the case of the divertor, the maximum allowable working temperature under neutron irradiation for the currently utilised copper alloy is 350 °C. To increase efficiency, it is necessary to develop heat sink materials for operating temperatures up to 550 °C. Metal matrix composites with a copper matrix reinforced with silicon carbide long fibres were investigated. SiC-fibre reinforced copper combines both high thermal conductivity and mechanical strength. SiC fibres were coated with a copper layer by electroplating and subsequently hot-isostatic pressed in a copper capsule to form a composite. Push out tests were carried out in order to investigate the bonding properties between fibres and matrix. An additional titanium interlayer was deposited on the fibres by magnetron sputtering to increase the bonding strength.