Response of mechanical properties and subsurface damage in β-SiC to temperature and crystal plane during nanoindentation simulation

A series of theoretical calculations based on molecular dynamics (MD) was carried out to investigate the ceramic material mechanical response of β-SiC. Importantly, the effect of temperature and crystal plane on material mechanical performance, correlative mechanisms of subsurface damage behavior, and otherness in the subsurface layer as well as explored and analyzed at nanoindentation process. MD calculation results show that the ambient temperature rises can promote SiC material dislocation generation, nucleation, and propagation, which leads to the degree of damage in the subsurface layer increases and material brittle failure occurs because of the concentration of internal stress in ceramic material. Moreover, it was discovered that dislocation ring was a microscopic phenomenon of the transformation from elastic deformation to plastic deformation of SiC, and the dislocation ring nucleus, dislocation ring growth, dislocation ring propagation, dislocation ring brittle fracture are the main plastic deformation characteristics of SiC during nanoindentation simulation. In addition, with the increase of temperature, the damage degree of subsurface layer is intensified. The direct driving force could induce partial phase transformation occurs for β-SiC material from cubic sphalerite structure to the hexagonal wurtzite structure. Moreover, the majority of amorphous atoms generated at low temperatures would decrease with increasing temperature. The results of this work can be to enrich understand the details information on dynamic microstructure evolution process, and the corresponding subsurface damage behavior at the atomic scale when materials are subjected to external working loads and extreme temperature.