Effect of helium on radiation damage in a SiC/C composite

In fusion reactor materials relatively large amounts of hydrogen and helium will be produced by nuclear reactions. While in metals and alloys the effe ct of helium on damage structure and mechanical properties is extensively d ocumented, such information is largely missing in ceramic materials. In the present study a silicon carbide-carbon composite was homogeneously implant ed with helium from a cyclotron. The damage microstructure after implantati on and after subsequent thermal annealing was investigated by transmission electron microscopy (TEM). Populations of bubbles inside the grains and alo ng grain boundaries are observed, with clear dependence of bubble appearanc e on the type of boundary. Effects on mechanical properties of SiC/C and of radiation damage on other SiC composites are discussed. (C) 2000 Elsevier Science Ltd and Techna S.r.l. All rights reserved.