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 effect of helium on damage structure and mechanical properties is extensively documented, such information is largely missing in ceramic materials. In the present study a silicon carbide–carbon composite was homogeneously implanted with helium from a cyclotron. The damage microstructure after implantation and after subsequent thermal annealing was investigated by transmission electron microscopy (TEM). Populations of bubbles inside the grains and along grain boundaries are observed, with clear dependence of bubble appearance on the type of boundary. Effects on mechanical properties of SiC/C and of radiation damage on other SiC composites are discussed.