Reinforcement with carbon nanotubes in aluminum matrix composites

Aluminum matrix composite rods in which tightly bonded multi-walled carbon nanotubes (MWNTs) are separately dispersed and uniaxially aligned have been fabricated by hot extrusion of ball-milled powders. The reinforcing efficiency of MWNTs in the composites follows the volume fraction rule of discontinuous fibers in the grain size range down to 70 nm.