Structural anisotropy effect on the nanoscratching of monocrystalline 6H-silicon carbide

Monocrystalline 6H-silicon carbide is a promising material for advanced components and devices; but is also a difficult-to-machine material due to its hardness, brittleness and structural anisotropy. With the aid of large-scale molecular dynamics simulations, this paper comprehensively studied the structural anisotropy effect on the nanoscratching of 6H–SiC. Six typical combinations of scratching plane and direction were selected, namely, (0001)<112‾0>, (0001)<11‾00>, (112‾0)<11‾00>, (112‾0)<0001>, (11‾00)<0001> and (11‾00)<112‾0>. It was found that the scratching-induced deformation morphology, activated dislocations and scratching forces varied significantly under different combinations of scratching conditions due to the strong anisotropy effect of the material. By evaluating the actual depth of cut, elastic recovery, surface roughness and maximum subsurface damage depth, basal plane (0001) along <11‾00> direction was identified as the best combination for conducting nanoscratching on 6H–SiC. Corresponding high-resolution TEM results show that the mechanism revealed by the MD analysis reflects the true deformation of the material.