Subsurface deformation and crack propagation between 3C-SiC/6H-SiC interface by applying in-situ laser-assisted diamond cutting RB-SiC

Reaction-bonded silicon carbide (RB-SiC) is considered as an excellent optical material in aerospace engineering. However, the multiple complex interfaces and high hardness make it difficult to be precisely machined. In this research, the in-situ laser-assisted diamond cutting was applied to precisely machining RB-SiC. Firstly, Raman spectroscopy was adopted to identify 3C-SiC and 6H-SiC components in RB-SiC. As following, the in-situ laser-assisted diamond cutting was experimentally carried out to analyze the subsurface deformation and fracture in detail. It was clarified that the cross slips and high-density stacking faults significantly enhance the plastic deformation of RB-SiC. Moreover, the dislocations rapidly plugged at the intersection of 3C-SiC/6H-SiC interfaces resulting in the lateral crack which propagates along the [111]//[0001] direction.