Review: carbon nanotube dispersal mechanisms in the fabrication of powder metallurgy metal matrix composites and effects on mechanical properties

This review outlines recent developments carried out by researchers in the fabrication of carbon nanotube metal matrix composites (CNT/MMCs) and their resulting material properties. More specifically, this review focuses on various CNT dispersal mechanisms in the fabrication of CNT/MMCs via the powder metallurgy method (PM). PM techniques have emerged as an attractive fabrication route for composite mixtures with constituents on the sub-micron to nano scale. The state and quality of CNT dispersion in the starting composite powder mixture is crucial to gain full advantage of subsequent consolidation/thermal processing phases in the PM fabrication route. Current review shows comprehensive approaches, undertaken globally, in obtaining optimal CNT dispersions in metal matrix systems utilising a variety of techniques. The present review brings into focus the critical issues which affect the mechanical performances of CNT reinforced MMCs that include: CNT dispersal , CNT/metal transition layer, compatibility of CNTs in metal systems, and CNT strengthening mechanisms.