Abstract
Carbon nanotube is considered to be an ideal reinforcing fiber of nanocomposite materials. However, the microscopic mechanism of reinforcement has not been fully understood yet. In this paper, to understand deformation and fracture mechanisms of nanocomposites, nano-tensile/compressive test, nano-bending and nano-cutting of nanotube/silicon nanocomposites are investigated by molecular dynamics simulation. The nanocomposite materials consist of armchair single-walled carbon nanotubes and silicon as a matrix.Firstly, results of nano-tensile/compressive show that mechanical properties such as Young′s modulus, maximum tensile strength depend on the orientation of nanotubes in terms of stress direction. For example, tensile tests show that the Young′s modulus and the maximum tensile strength increase 28% and 19% respectively, comparing with those of pure silicon when the nanotube axis matches the tensile direction. Secondly, results of nano-bending show that the fracture toughness is sensitive to the location of nanotubes in the matrix. The fracture toughness of nanocomposites varies from a 40% increase to a 17% decrease comparing with that of pure silicon.Finally, results of nano-cutting show that the more stable ductile-mode machining of the nanocomposite materials is observed than that of pure silicon. This phenomenon is insensitive to the orientation of nanotubes in terms of the cutting direction.
