Enhancing tensile and compressive strength of magnesium using ball milled Al+CNT reinforcement

Abstract

In this work, Mg/Al-CNT nano-composites were fabricated using powder metallurgy route involving microwave assisted rapid sintering and hot extrusion. Ball milled Al-CNT particles comprising different contents of CNTs coated with fixed amount of Al were used for strengthening. Microstructural characterization of these Mg/Al-CNT nano-composites reveal reasonably uniform distribution of Al-CNT particles up to CNT content of 0.30% by weight, significant grain refinement and the presence of minimal porosity compared to monolithic Mg. Importantly, for the nominally identical processing conditions, the textures of as-extruded nano-composite specimens is significantly influenced by the presence of Al-CNT particles. Nano-composite configurations exhibit different tensile and compressive response as a function of CNT content. Among the different Mg/Al-CNT formulations synthesized, the Mg/Al-CNT configuration with Al-CNT particles composition of 1.00% Al and 0.30% CNT by weight (Mg/1.00Al-0.30CNT) exhibit higher tensile yield strength (0.2% YS), ultimate tensile strength (UTS) and failure strain (FS) (up to +72%, +48%, +9%, respectively) compared to monolithic Mg.In terms of compressive response, it exhibits the best overall compressive properties compared to the monolithic Mg with an improvement of 63% in the compressive yield strength (0.2% CYS) and 80% in ultimate compressive strength (UCS), but failure strain was compromised. © 2011 Elsevier Ltd.