EFFECTS OF FAST-NEUTRON IRRADIATION ON PYROLYTIC SILICON CARBIDE

Samples of pyrolytic polycrystalline β-silicon carbide were irradiated to 2.0 to 4.2 × 1021 nvt (E > 0.18 MeV) at temperatures between 460 and 1040 °C. The samples showed an isotropic linear expansion that decreased with increasing irradiation temperature from 0.35 % at 460 °C to 0.05% at 1040 °C. The lattice parameter changes were equal to the macroscopic dimensional changes within experimental accuracy. Irradiation caused a slight increase in X-ray line broadening that was attributable to the generation of internal strains. There was no significant change in Young's modulus or the modulus of rupture. © 1969.