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 degreesC. Measured swelling values yielded approximately at the lower edge of neutron-induced swelling data band at T similar to<600 degreesC. A fusion-relevant helium-to-dpa condition significantly enhanced swelling at 400 <similar toT <similar to800 degreesC. The temperature dependence of saturated swelling both with and without helium co-implantation suggested a transient in defect behavior between 800 and 1000 degreesC. 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. (C) 2002 Elsevier Science B.V. All rights reserved.