Irradiation-induced microstructural evolution and swelling of 3C-SiC

In this study, an ion-irradiated single crystal 3C-SiC under fluences of up to 20 dpa at 400-1350 °C was examined using synchrotron based X-ray diffraction and high resolution transmission electron microscopy. Interstitial clusters, dislocation loops, Frank loops, stacking fault loops, and voids in 3C-SiC were investigated. The high resolution TEM results show that clusters collapsed to {1 1 1} small loops when their size reached few nm with increasing temperature, and gradually develop into Frank loops with an added atomic layer along {1 1 1} at 1000 °C. Interplanar spacing information of single crystal SiC was obtained from synchrotron XRD radial scan measurements. Irradiation-induced volume swelling at 400-1350 °C was measured, and the anisotropic (a = b < c) swelling behavior of SiC was confirmed. In addition, humps on the right side of SiC (0 0 2) were observed, which suggested that C⁺/Si⁺-Si〈1 0 0〉 and/or C⁺/Si⁺-C〈1 0 0〉 dumbbells gave rise to diffuse scattering.