Mechanical alloying of multi-walled carbon nanotubes and aluminium powders for the preparation of carbon/metal composites

Interactions between carbon nanotubes (CNTs) and aluminium particles during the mechanical alloying (MA) via ball milling have been investigated from the viewpoint of particle behaviour with the aim at developing CNT-dispersed Al matrix composites based on powder metallurgy routes. It was observed that the use of the curly small-diameter multi-walled carbon nanotubes (MWCNTs) in the MA prevented the agglomeration of composite powders, which is attributed to the beneficial role of the MWCNTs as grinding aids. It was also deduced from the mechanical properties of the composite samples, prepared from the ball-milled powders, that such prevention of the particle agglomeration did not hinder the homogeneous distribution of the CNT reinforcements within the Al matrix. It is suggested that careful choices of the sizes of CNTs and Al powders would allow fine-grinding of composite particles with uniformly distributed CNT reinforcements thereby ensuring improved properties of the final composites produced by low-temperature compacting.