Structural Analysis for Tensile Behavior of Silicon-Carbon Core-Shell Nanotube

This paper presents a molecular dynamics study on the tensile behavior of carbon nanotubes (CNT) with or without nanowire of Si (SiNW) encapsulated. Compared to the CNT without SiNW, the CNT with the SiNW (denoted as SiNW@CNT) shows a decreased tensile strength but an increased maximum tensile deformation rate. The micromechanisms of the different tensile behaviors were explored through the structural analysis including the radial distribution function, the bond angle distribution function, and the statistics of the polygon defects. The results showed that the C-C bond in the CNT under the maximum tensile deformation becomes longer and more uniform due to the van der Waals force between the SiNW and the CNT, which accounts for the change in the macroscopical tensile behavior. Moreover, it has been found that after tensile fracture, the CNT mainly form long chains consisting of triangle, pentagon, and heptagonal defects, while SiNW@CNT cannot form long chains due to the lack of triangular defects. These differences in the microstructures are probably because the C-C bonds in the SiNW@CNT can be strengthened by the SiNW. The results provide a better understanding of the fracture of the CNT and its nano composites, and have certain reference value for the application of the SiNW@CNT.