Structural damage and hardness evolution in pressureless-sintered α-SiC implanted with 500 keV He-ions

Pressureless-sintered SiC is a promising candidate for nuclear applications due to its high strength, low neutron cross-sections, low cost and easy to produce large and complex components. In the present study, pressureless-sintered α-SiC samples were implanted with 500 keV He ions to 1.0 × 10¹⁷ ions/cm² at room temperature (RT), 500 °C and 800 °C. The irradiation induced microstructural damage and hardening were measured by grazing incident X-ray diffraction, Raman spectroscopy, transmission electron microscopy and nanoindentation technique. Results showed that He implantation induced lattice disorder and swelling, He bubbles and hardening. When the implantation temperature was RT, the lattice disorder and swelling was the most significant, and an amorphous band within the damage peak region was observed. With increasing implantation temperatures, lattice disorder and swelling weakened, but no amorphous layer occurred. The hardening degree was minimal at RT and maximum at 500 °C, which attributed to the softening effect of amorphous layer and pinning effect of the implantation induced defects.