Interface tailoring to enhance mechanical properties of carbon nanotube reinforced magnesium composites

This study highlights the use of a metallic coating of nanoscale thickness on carbon nanotube to enhance the interfacial characteristics in carbon nanotube reinforced magnesium (Mg) composites. Comparisons between two reinforcements were targeted: (a) pristine carbon nanotubes (CNTs) and (b) nickel-coated carbon nanotubes (Ni-CNTs). It is demonstrated that clustering adversely affects the bonding of pristine CNTs with Mg particles. However, the presence of nickel coating on the CNT results in the formation of Mg2Ni intermetallics at the interface which improved the adhesion between Mg/Ni-CNT particulates. The presence of grain size refinement and improved dispersion of the Ni-CNT reinforcements in the Mg matrix were also observed. These result in simultaneous enhancements of the micro-hardness, ultimate tensile strength and 0.2% yield strength by 41%, 39% and 64% respectively for the Mg/Ni-CNT composites in comparison with that of the monolithic Mg. (C) 2014 Elsevier Ltd. All rights reserved.