Experimental and numerical investigation into the effect of carbon nanotube buckling on the reinforcement of CNT/Cu composites

Carbon nanotube reinforced copper matrix (CNT/Cu) composites with high strength and good damping have been developed using acid treatment, sintering processes and consolidation techniques. Strengthening of the composites as a result of nanotube buckling has been demonstrated by experimental nanoindentation tests and molecular dynamics (MD) simulations. The experimental results show that the buckling behavior of additional CNTs in the CNT/Cu composites varies with the slenderness ratio of CNTs. Specifically, this study shows that the significant buckling behavior of CNTs in the CNT/Cu composites where the shorter CNTs (with a smaller slenderness ratio) give rise to a global buckling and the slender CNTs (with a larger slenderness ratio) induce local buckling. The MD simulation results reveal that the buckling behavior of the CNTs plays a key role in increasing the mechanical strength of CNT/Cu composites by acting as a “buffer” in releasing excess strain in the Cu matrix.