Unveiling anisotropic behavior in 3C-SiC via in situ nano-scratching

Cubic silicon carbide (3C-SiC) is an excellent material for applications in extreme conditions due to its exceptional mechanical and physical properties. However, studying its material removal and tribological performance is challenging due to its limited depth of growth and high brittleness. In this study, we investigated the anisotropic performance of a thick 3C-SiC single crystal (∼20 µm) through in-situ nano-scratching in the scanning electron microscope. We performed nano-scratching on the (100) plane along the [110] and [100] directions. The [110] orientation exhibited greater hardness during scratching compared with the [100] orientation, resulting in a lower material removal rate and a higher coefficient of friction. Atomic-level observations of the scratched groove revealed that plastic material removal was accomplished through dislocation slip and significant lattice distortion. The subsurface in both scratching directions primarily experienced perfect dislocation slip during the plastic deformation stage. Additionally, the intense strain caused polycrystallization, which was identified as a significant deformation mechanism in 3C-SiC.