Reinforcing effects of carbon nanotubes in structural aluminum matrix nanocomposites

The reinforcing effects of carbon nanotubes (CNTs) are investigated for aluminum matrix composites. The composites present a strong bonding between CNTs and the aluminum matrix using a controlled mechanical milling process, producing a network structure of aluminum atoms around CNTs. At the same time, CNTs that are dispersed during the milling process can be located inside aluminum powders, thereby providing an easy consolidation route via thermomechanical processes. A composite containing 4.5 vol% multiwalled CNTs exhibits a yield strength of 620 MPa and fracture toughness of 61 MPa·mm^1/2, the values of which are nearly 15 and seven times higher than those of the corresponding starting aluminum, respectively.