Chemical and mechanical treatments for enhancement of carbon nanotube reinforced aluminum matrix composites

Abstract

A widespread application of carbon nanotube (CNT) and its metal matrix composites (MMCs) has not been achieved due to difficulty to disperse CNT in the matrix to efficiently obtain the excellent properties of CNT. In this study, CNT/Al composites were fabricated by uniformly dispersing CNT in Al matrix using chemical and mechanical treatments, which include untangling CNT in an organic solvent (DMAc) with a certain dispersant such as potassium carbonate (K2CO3) or ammonium carbonate ((NH4)2CO3)), dry ball milling and post-sintering repeated hot rolling. The composites were consolidated by spark plasma sintering (SPS). It was found that chemical treatments with ammonium carbonate were more effective to untangle CNT with less damage, while CNT/Al composites with CNT treated by potassium carbonate showed higher dispersibility of CNT in Al matrix. It was also seen that the post-SPS repeated hot rolling can highly improve dispersibility of CNT as well as mechanical properties such as hardness, tensile strength and deformability of the composites.