Recrystallization of amorphized Si during micro-grinding of RB-SiC/Si composites

• Amorphization of Si and SiC was induced during micro-grinding of RB-SiC/Si.
• Recrystallization of amorphized Si was identified by XRD.
• Preferred orientation growth of Si during micro-grinding occurred.

X-ray diffraction (XRD) was performed to investigate the phase transformation of Reaction-Bonded SiC/Si composites (RB-SiC/Si) induced by micro-grinding. The results showed that amorphization (High Pressure Phase Transformation, HPPT) occurred for both SiC and Si phases in the outmost layer, and the amorphization degree dropped as the feed rate changed from 3 mm/min to 0.1 mm/min. Moreover, we firstly found that recrystallization of amorphized Si appeared in preferred orientation under grinding. Specifically, preferred Si(111) growth occurred at a lower feed rate attributed to the more obvious annealing effect, while preferred Si(220) recrystallization developed at higher feed rate due to the greater strain. Theoretical analysis based on the crystal structure of Si yield good consistence.