Temperature dependence of mechanical properties and defect formation mechanisms in 3C-SiC: A molecular dynamics study

Nanoindentation simulations of single-crystalline cubic silicon carbide across a temperature range of 300-2000 K are performed using molecular dynamics to elucidate the temperature dependence of mechanical characteristics and lattice defect formation mechanisms. The load-displacement curves obtained by our simulations indicate weak temperature dependence of elastic responses and strong temperature dependence of plastic deformation. We reveal that the critical mean contact pressure, which is a criterion for the plasticity onset decreases with temperature. Meanwhile, plastic deformation at low temperatures starts with the nucleation and expansion of perfect dislocations, whereas the perfect dislocations dissociate into Shockley partial dislocations with stacking faults at high temperatures. After unloading, symmetric impression patterns caused by atomic arrangements on surfaces are observed at 300 K, whereas atomic pile-ups closely related to dislocation movement are formed around impressions at 2000 K. Additionally, the ductile behavior on a (1 1 1) surface indent is more affected by temperature than that on a (001) surface.

Automated summary

Nanoindentation simulations were conducted on single-crystalline cubic silicon carbide to investigate the temperature dependence of mechanical characteristics and lattice defect formation mechanisms. The results showed weak temperature dependence of elastic responses but strong temperature dependence of plastic deformation. The critical mean contact pressure for plasticity onset decreased with increasing temperature. At low temperatures, plastic deformation started with the nucleation and expansion of perfect dislocations, while at high temperatures, the dislocations dissociated into Shockley partial dislocations with stacking faults. Different atomic patterns were observed on the surfaces after unloading at different temperatures, and the ductile behavior was more influenced by temperature on the (1 1 1) surface than on the (001) surface.