Molecular dynamics simulation of shearing deformation process of silicon nitride single crystal

Abstract

Shear deformation properties of α and β silicon nitride single crystals are investigated using the classical molecular dynamics (CMD) method. Four cases of shearing directions are analyzed, which were reported to be slip system on the basis of experimental observations. The simulation results show that shear deformation does not occur in one of the experimentally predicted slips (α – {1 1 ̄ 0 1} 〈1 1 2 ̄ 0〉) . In this case the crystal is broken abruptly under shear deformation. In the case of the β crystal (β – {1 0 1 ̄ 0} 〈0 0 0 1〉) , a sharp slip with edge dislocation can be found. The dislocation core width and speed are estimated. Finally one of the CMD results is compared with the corresponding first principle density functional calculation results, and it is shown that the validity about shearing CMD simulation of the 3-body interatomic potential was proposed by Vashishta.