Fabrication of Carbon Nanotube-Reinforced 6061Al Alloy Matrix Composites by an In Situ Synthesis Method Combined with Hot Extrusion Technique

Carbon nanotube （CNT）-reinforced 6061Al alloy matrix composites were prepared by chemical vapor depo- sition （CVD） combined with hot extrusion technique. During the preparation process, the 6061Al flakes obtained by ball milling of the 6061Al spherical powders were subjected to surface modification to introduce a hydrophilic polyvinyl alcohol （PVA） membrane on their surface （6061Al@PVA） to bond strongly with nickel acetate [Ni（II）]. Then the 6061Al@PVA flakes bonded with Ni（II） were calcined and reduced to Ni nanoparticles, which were then heat-treated at 580 ℃ to remove PVA for obtaining even Ni/6061Al catalyst. After that, the as-obtained Ni/6061Al catalyst was employed to synthesize CNTs on the surface of the 6061Al flakes by CVD. After hot extrusion of the CNT/6061Al composite powders, the as-obtained CNT/6061Al bulk composites with 2.26 wt% CNTs exhibited 135% increase in yield strength and 84.5% increase in tensile strength compared to pristine 6061Al matrix.