This review summarizes the work carried out in the field of interface study in carbon nanotube reinforced aluminum （CNT/A1） composites. Much research work has been conducted to reveal the evolution of CNT/A1 interface in producing the composite with the purpose of achieving uniform distribution of CNTs and tight interfacial bonding. The effect and principles of coating were reviewed along with the illustration of ＂intermetallic interphases＂ design. Different roles of CNT/Al interface in structural and functional application were elucidated, and the future work that needs attention was addressed.
Realizing the uniform dispersion of nanocarbons such as carbon nanotube and graphene in metals, is an essential prerequisite to fully exhibit their enhancement effect in mechanical, thermal, and electrical properties of metal matrix composites(MMCs). In this work, we propose an effective method to achieve uniform distribution of nanocarbons in various metal flakes through a slurry-based method. It relies on the electrostatic interactions between the negatively charged nanocarbons and the positively charged metal flakes when mixed in slurry. For case study, flake metal powders(Al, Mg, Ti,Fe, and Cu) were positively charged in aqueous suspension by spontaneous ionization or cationic surface modification. While nanocarbons, given examples as carboxylic multi-walled carbon nanotubes, pristine single-walled carbon nanotube, and carbon nanotube–graphene oxide hybrid were negatively charged by the ionization of oxygen-containing functional groups or anionic surfactant. It was found that through the electrostatic interaction mechanism, all kinds of nanocarbons can be spontaneously and efficiently adsorbed onto the surface of various metal flakes. The development of such a versatile method would provide us great opportunities to fabricate advanced MMCs with appealing properties.
Powder metallurgy （PM） is one of the most applied processes in the fabrication of metal matrix composites （MMCs）. Recently, a novel PM strategy called flake PM was developed to fabricate MMCs with nano-laminated or hierarchical architectures. The name ＂flake PM＂ was derived from the use of flake metal powders, which could benefit the uniform dispersion of reinforcements in the metal matrices and thus result in balanced strength and ductility. Flake PM has been proved to be successful in the dispersion of nano aluminum oxides, carbon nanotubes, graphene nano-sheets, and microsized B4C particles in aluminum or copper matrix. This paper reviews the technique and mechanism developments of flake PM in previous studies, and foresees the future develop of this new fabricating method.
