Microstructural evolution, swelling and hardening of CVD-SiC induced by He ions irradiation at 650 °C

In the present study, chemical vapor deposited (CVD) SiC samples were irradiated by 500 keV He ions to different doses at 650 °C. The microstructural evolution, surface swelling and nanohardness change caused by irradiation versus He ion dose were investigated using TEM, AFM and nanoindentation. Results showed that a high number density of He bubbles and dislocation loops were formed in the sample irradiated to the high dose, resulting in a swelling of 1.53%. Meanwhile, the hardness of the samples increased after He ions irradiation, which was attributed to the pinning effect of the irradiation induced defects and bubbles. The irradiation hardening degree increased and tended to be saturated with the increasing He ion dose.