Preparation and properties of dual-matrix carbon nanotube-reinforced aluminum composites

Recent studies on Aluminum-Carbon Nanotube (Al/CNT) composites reported improved strength with the addition of small amounts of CNTs. Most studies reported low ductility which is limiting the potential of such materials. In the current study, a novel Al/CNT microstructural design was introduced to improve ductility while maintaining adequate strength. Al/CNT composites were prepared as: Single Matrix (SM) and Dual Matrix (DM) structures. The SM composites were synthesized by dispersing CNTs in aluminum powders. The DM composites were produced by embedding pre-processed SM Al/CNT powders into a secondary matrix of soft aluminum. Two overall CNT compositions, 1 wt.% and 2.5 wt.%, were synthesized. The DM approach was found to lead to enhancements of up to 14.8% in ductility compared to SM composites of the same CNT content. Nanoindentation hardness and modulus of DM composites were found to be comparable to their SM counterparts.