Effect of point defects and low-density carbon-doped on mechanical properties of BNNTs: A molecular dynamics study

By the employment of molecular dynamic simulations (MD), we investigated the mechanical properties of defective single-walled Boron nitride nanotubes (SWBNNTs) with zigzag and armchair chirality's. After removing different numbers of atoms from nanotubes' surface and putting samples under uniaxial tensile loading at constant strain rate Young's modulus, failure stress and failure strain were calculated and the results demonstrated that the young's modulus of armchair structures was higher than those of zigzag structure in every type of vacancy defect. However, failure strain and stress of zigzag structure were higher than armchair except in three atom vacancy defect type 2 in which one B and two N atoms were deleted from the surface. Furthermore, we considered the mechanical behavior of BNNTs with different numbers of doped carbon atoms. We found that Young's modulus did not have a constant trend via rising in the number of carbon. The armchair structure showed higher or equal moduli compared to zigzag one except in one carbon-doped BNNTs. The maximum modulus of doped structures was observed in configuration antheacene for both chirality's. Failure properties of zigzag doped BNNTs with 2, 4 and 6 carbon atoms and also 3 carbon rings doping were higher than those of armchair structure while in other doped BNNTs (2,4 and 5 carbon rings) reverse results were collected.