Combination of hot extrusion and spark plasma sintering for producing carbon nanotube reinforced aluminum matrix composites

Aluminum (Al)/carbon nanotube (CNT) composites with nanoscale dispersion and regular orientation of the CNTs were fabricated by a combination of some advanced powder processes. The CNTs were well dispersed onto the Al particles by a nanoscale dispersion method. Moreover, the highly densified CNT composites were prepared by spark plasma sintering and subsequent hot extrusion. Microstructural observations by optical, field-emission scanning electron, and high-resolution transmission electron microscopies confirmed that the sintered Al/CNT compact and extruded bulk material had a good dispersion of oriented CNTs. Raman spectroscopy showed that the processing did little damage to the CNTs. As a result, the composites exhibited tensile strengths that were thrice larger than pure aluminum because of the CNT reinforcement.