Tensile mechanical behaviors of cubic silicon carbide thin films

Abstract

Molecular dynamics (MD) methods using Tersoff potential are employed to study the nanomechanical behaviors of 3C-SiC (010) thin films under [100]-oriented tension. In this work, the Young’s modulus, tensile strength and elongation of thin films are compared with those of the bulk 3C-SiC for different temperatures. The results show that Young’s modulus of the nanofilms is size dependent and softer than its bulk counterpart. It is found that Young’s modulus decreases as much as 24.7% when the thickness of the thin film reduces to unit lattice, which suggests that size effect could not be neglected when the characteristic length shrinks down to several nanometers. When the thickness of the thin films is more than 10nm, and thin film value converges to the bulk value. As the increment of thin film value is very slow, the size effects of 3C-SiC could be neglected. In addition, the reduction in Young’s modulus of the nanofilm with increasing temperature exhibits a nonlinear trend. Moreover, the simulations demonstrate that the tensile strength and elongation of bulk 3C-SiC also decreases with the increase of temperature. Despite partial degradation, SiC nanofilm maintains its mechanical properties largely at elevated temperatures, which makes it attractive for applications in high temperature environment.