Improved dispersion of carbon nanotubes in aluminum nanocomposites

In this study, we investigated the influence of the dispersion technique of carbon nanotubes (CNT) in the production of aluminum matrix nanocomposites. Three production routes using different dispersion techniques were tested: in R1 route the CNT were dispersed using an ultrasonic bath; in R2 route the dispersion was achieved by ultrasonication, while in R3 route the dispersion and mixing were performed by ultrasonication CNT and Al powders. Nanocomposites with several CNT contents (0.25–2.0 wt.%) were produced by conventional powder metallurgy procedures. Microstructural characterization by scanning and transmission electron microscopies revealed that the best dispersion of the CNT is obtained using R3 route. Nanocomposites with 0.75 wt.% of CNT exhibit well dispersed and embedded nanotubes and the highest hardness and tensile strength. The observed 200% increase in the tensile strength attested the strengthening effect of the CNT and the efficiency of the new dispersion treatment (R3 route).