Mechanical Behavior of Multiwalled Carbon Nanotube Reinforced 7075 Aluminum Alloy Composites Prepared by Mechanical Milling and Hot Extrusion

posted on 06.02.2019 by Eduardo Uriza-Vega, Caleb Carreño-Gallardo, Claudia López-Meléndez, Eduardo Cuadros-Lugo, Raúl Pérez-Bustamante, Ernesto Ledezma-Sillas, Jose Martin Herrera-Ramirez

In this paper, multiwalled carbon nanotubes (MWCNTs) were synthesized by spray pyrolysis to be used later as material reinforcement in the production of MWCNTs/Al7075 aluminum composites. Both, MWCNTs and MWCNTs/Al7075 composites were microstructurally and mechanically characterized. Scanning electron microscopy (SEM) analysis shows MWCNTs formed by multiple layers rolled on themselves forming a tube shape with lengths up to 1300 µm and diameters ranging from 55 to 120 nm. MWCNTs were added to the aluminum matrix in different concentrations up to 3.0 wt%. Their dispersion in the aluminum matrix was carried out by ultrasonic/methanol method followed by high-energy mechanical milling process. The effect of MWCNTs on the morphology and mechanical behavior of composites were evaluated. Results indicate that a homogeneous dispersion of CNTs was obtained as a consequence of the dispersion routes used in the production of composites, observing no damage on their morphology. The mechanical behavior of the composites shows a noticeable improvement for MWCNTs concentrations above 2.0 wt%, with ductility similar to that found in the literature for the Al7075 commercial alloy.