In-situ TEM investigations on the microstructural evolution of SiC fibers under ion irradiation: Amorphization and grain growth

SiC/SiC composites are attractive candidates for many nuclear systems. As reinforcements, SiC fibers are critical to the in-service performance of composites. In this work, the temperature effects on the irradiation-induced microstructural evolution of Cansas-III SiC fibers were investigated using in-situ transmission electron micro-scopy (TEM). With in-situ 800 keV Kr ion irradiation, at room temperature (RT) the SiC fiber experienced heterogeneous amorphization and became completely amorphous at-2.6 dpa. Above the critical temperature of crystalline-to-amorphous (Tc), SiC fibers underwent a simultaneous process of carbon packet disappearance and nano-grain growth at 300 degrees C and 800 degrees C. Possible mechanisms were discussed.