The effects of neutron irradiation on microstructural evolution and the resultant changes
in physical and mechanical properties are of critical importance for the development of
silicon carbide (SiC) materials for nuclear applications. This study neutron-irradiated βSiC under a wide range of conditions at temperatures between 235 and 750°C and neutron
doses of 0.01–11.8 displacements per atom, and then evaluated the effects on the SiC
structure using Raman spectroscopy. The SiC optical phonon lines were shifted to lower
wavenumbers by irradiation. Correlations were found among the wavenumber of the
longitudinal optical phonon line, irradiation-induced swelling, and irradiation
temperature. The peak shift also correlated indirectly with decreasing thermal
conductivity of irradiated SiC. The irradiation-induced peak shift is explained by
combinations of lattice strain, reduction of the elastic modulus, and other factors
including decreasing coherent domain size. These findings bridge irradiation-induced
microstructural changes and property changes and illustrate how Raman spectroscopy is
a useful tool for nondestructively assessing irradiated SiC materials for nuclear
applications.