Influence of acid-treated time of carbon nanotubes on mechanical property in carbon nanotubes reinforced copper matrix composites

Carbon nanotubes reinforced copper matrix (CNT/Cu) composites with high mechanical properties were successfully fabricated by wet mixing and spark plasma sintering (SPS). The effects of CNTs acidification time and CNTs content on the microstructure and mechanical properties of composites were characterized by SEM, FTIR, Raman, HR-TEM and tensile tests. The composites with 24 h acid-treated CNTs (0.5 wt%) and sintered at 837 K had the most optimal mechanical properties, which primarily stemmed from the use of oxygen as an atomic transient agent to form solid Cu-CNT interfacial bonding, the complete densification of the composites and the uniform dispersion of the CNTs. From the density functional calculations, the strong contact mode of Cu2O-CNT is conducive to the improvement of mechanical properties. In addition, the reinforcing effect of surface modification at different acidification times of CNTs was studied and discussed by the strengthening models. This study describes an approach for uniformly dispersing CNTs to enhance the mechanical properties of CNT/Cu composite materials with strong interface bonding and enhancement.