Abstract: Tension simulations of[001]monocrystalline face-centered cubic SiC(β-SiC) and C-doped β-SiC bulks are performed with molecular dynamics method to investigate intrinsic deformation mechanisms and mechanical behaviors of β-SiC under strain rates of 5×10⁸/s,1×10⁹/s,1×10¹⁰/s.It is found that Si-C sp³ and C-C sp³ bonds respectively transform to Si-C sp² and C-C sp² bonds as soon as the strains reach certain critical values.As certain amounts of sp² bonds are formed,instable fractures emerge in β-SiC.Since C-C sp² bonds are formed earlier than Si-C sp² bonds,the doping of C elements leads to the decrease of strength,Young's modulus and tension fracture strain of β-SiC.In addition,it is found that the strain rates have effects on tensile-strength,but not on Young's modulus.

Key words: SiC, mechanical behavior, chemical bonds, molecular dynamics