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.

Automated summary

SiC/SiC composites are promising materials for nuclear systems, and SiC fibers play a critical role in the performance of these composites. This study investigated the microstructural evolution of Cansas-III SiC fibers under temperature effects using in-situ transmission electron microscopy. The results showed that at room temperature, the SiC fibers experienced heterogeneous amorphization and became completely amorphous at a certain dose. At temperatures above the critical temperature for crystalline-to-amorphous transition, the fibers underwent carbon packet disappearance and nano-grain growth. Possible mechanisms were discussed.