Enhanced interfacial bonding and mechanical properties in CNT/Al composites fabricated by flake powder metallurgy

A flake powder metallurgy route consists of a slurry based dispersion process and a short time ball milling process was proposed to fabricate strong and ductile CNT/Al composites reinforced with high content CNTs. To improve the interfacial bonding, the CNT/Al nanoflake powders prepared through slurry based dispersion process would go through a short time high energy ball milling process to break native Al2O3 skin and embed CNTs into Al matrix. With the dispersion homogeneity and well-maintained structural integrity of CNTs achieved by the slurry based dispersion, and improvement of interfacial bonding from non-bonding to physical bonding/diffusion assisted bonding and partial reaction bonding through the short time ball milling, an enhancement of tensile strength from 298 to 406 MPa and ductility from 1.9 to 8.8% was obtained for the 2 h ball-milled 3 vol.% CNT/Al composites, compared to the composites fabricated by sole slurry based dispersion process. It also outperformed that fabricated by direct high energy ball milling, indicating the flake powder metallurgy method could provide a good coordination between the CNT dispersion homogeneity, structural integrity and interfacial bonding. (c) 2018 Elsevier Ltd. All rights reserved.