The effect of the addition of CNTs on the microstructure, densification and mechanical behavior in al-CNT-al2o3 hybrid nanocomposites

Abstract

The effects of the addition of carbon nanotubes (CNTs) on the morphology and microstructure of Al-Al2O3 nanocomposites and the subsequent effects on their densification and mechanical behavior are studied. From the morphologic study, ball milling was found to be more intensified in the presence of 2 wt.% of CNTs wherein steady state was reached after 5 h of milling. The addition of CNTs as a mixing agent facilitates dispersion of Al2O3 nanoparticles and exerts extensive grain refinement. Compressibility and sinterability were found to be positively correlated with the milling time. Compressibility and sinterability were improved by increasing milling time owing to severe particle size reduction and minimizing the agglomeration of reinforcement particles. The micro-hardness (HV), nano-hardness (HN) and Young’s modulus (E) values of Al-2CNT-10Al2O3 nanocomposites increased by ~ 19%, 26% and 34%, respectively, as the milling time proceeds. At each milling time, Al-2CNT-10Al2O3 nanocomposites possess superior mechanical properties compared with Al-10Al2O3 nanocomposites owing to the morphologic and microstructural variations caused in the presence of CNTs.