The influences of irradiation temperature and helium production on the dimensional stability of silicon carbide

Isotropic volume expansion, or swelling, is a well-known irradiation-induced phenomenon for silicon carbide (SiC), as observed after neutron irradiation. In this work, the influences of irradiation temperature and helium production on fluence-dependent swelling behavior in cubic SiC were characterized following the establishment of an experimental technique to determine ion-irradiation-induced swelling within an accuracy of <0.02%. Saturation swelling behavior was confirmed at temperature >200 °C. Measured swelling values yielded approximately at the lower edge of neutron-induced swelling data band at T ∼<600 °C. A fusion-relevant helium-to-dpa condition significantly enhanced swelling at 400<∼T<∼800 °C. The temperature dependence of saturated swelling both with and without helium co-implantation suggested a transient in defect behavior between 800 and 1000 °C. The surviving defect production efficiency in heavy-ion irradiated SiC at 333 K was very roughly estimated to be 20% from low-dose swelling data.