Study of the mechanical and workability properties of extruded aluminium (Al6061) based composites reinforced with MWCNTs

In this study, the microstructure and mechanical properties of extruded aluminium (Al6061) based composites reinforced with multiwall carbon nanotubes (MWCNTs) were investigated. Composites with varying volume fractions of MWCNTs (1 vol% and 3 vol%) were fabricated initially using high energy ball milling, followed by compaction and sintering. Hot extrusion was carried out for the developed composites at different extrusion temperatures, extrusion ratios and die angles. SEM analysis of the extruded composites showed good dispersion of the MWCNTs within the Al matrix alloy. Improvements in micro-hardness and compressive strength were observed in the extruded composites with 3 vol.% MWCNTs without any deterioration in elongation. In addition, the workability behaviors of the com-posites were investigated by a cold upsetting test. The pore reopening tests were performed to confirm the closure of pores after the extrusion and to further analyze the densification of the composites. The results for the densification process based on extrusion confirmed that the pores turned into spherically closed pores. For typical cases, the pores did not reopen even after increasing the strain therefore, additional forming was possible up to large deformations. (C) 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).