Manufacture of composite materials and their behaviour under loading conditions relevant for application in fusion reactors

In the present work 5 Si, Ti, B and C based ceramic composites have been optimised with respect to an application as material for the first wall of future fusion reactors like ITER or NET. SiC/C, SiC/B4C, TiC/B4C/C, SiC/B4C/C and SiC/TiC/B4C/C have been investigated, manufacture, characterisation and bonding of composites with metallic cooling structures made of the Mo alloy TZM were included. In the present work the most important test facility for characterisation of the developed composites was the electron beam facility JUDITH, with which instationary and stationary loading were possible. Measurement of the erosion rates and analysis of the damage after short high heat flux pulses was important for the evaluation of the different materials and the prediction of their behaviour in future fusion devices. The surface of the specimens was loaded with the electron beam of the 60 kW-facility in the hot cells of the Forschungszentrum Juelich. The power density was varied between 400 MW/m2 and 4 GW/m2. Finite element calculation were used to calculate the stresses and temperatures. Temperatures have been compared with measurement with thermocouple elements during loading. For the investigation of the stationary loading and hence the simulation of the normal operation mode of a fusion reactor, those materials, which have been optimised with respect to erosion rates, were bonded to a metallic cooling structure. (orig.)