Revealing the deformation mechanisms of 6H-silicon carbide under nano-cutting

6H silicon carbide (6H-SiC) is one of the most commonly used polytypes in commercial SiCs, such as its applications in high-temperature electronic devices, ultra-precision micro/nano dies and high-performance mirrors. However, the deformation mechanisms of 6H-SiC under nano-machining are unclear. This has significantly hindered the development of the material's ductile-regime and damage-free machining for micro/nano and miniaturized surfaces. This paper aims to explore such deformation mechanisms with the aid of large-scale molecular dynamics analysis. The results showed that with increasing the depth of cut 6H-SiC undergoes transition from elastic deformation to continuous plastic deformation and then to intermittent cleavage. A dislocation and structural analysis revealed that the plastic deformation of 6H-SiC can be realised via phase transformation from the Wurtzite structure to an amorphous structure, and/or through dislocations on the basal plane and/or pyramidal plane.