Fabrication of CNT/Al composites with low damage to CNTs by a novel solution-assisted wet mixing combined with powder metallurgy processing

A novel solution-assisted wet mixing processing was developed to efficiently produce CNT/Al composite powders . CNTs were firstly dispersed in zwitterionic surfactant aqueous solution, and then the flaky Al powders , produced from spherical Al powders by ball milling , were mixed with the CNT solution to adsorb the dispersed CNTs in the solution. It was indicated that CNTs could be uniformly adsorbed onto the flaky Al powders and CNT/Al powders with a maximum CNT concentration of 7.5   vol% could be obtained after filtering and drying. 1.5 and 3   vol% CNT/Al composites were then fabricated using the resultant composite powders through a powder metallurgy route. CNTs with average lengths of 0.9   μm and well-retained wall structure were uniformly dispersed in the Al matrix and aligned arrangement of CNTs was achieved after hot forging . Furthermore, it was found that most of CNTs were distributed at the grain boundaries and the CNT-Al interfaces were well bonded. The strengths of the CNT/Al composites were significantly increased, which could be attributed to the efficient load transfer of CNTs.