Search

Abstract: Aluminum-based nanocomposites were produced using multiwalled carbon nanotubes (MWCNTs) dispersion by mechanical milling (MM) followed by sintering and hot extrusion. MWCNTs showed stability after MM and thermo-mechanical processes. Excellent adhesion of nanotubes to Al-matrix was observed. Formation of an amorphous interface between nanotubes and aluminum matrix in nanocomposites was observed by TEM. This amorphous layer is probably responsible of the excellent adhesion of MWCNTs to the aluminum matrix. [Copyright &y& Elsevier]

Abstract: Novel Al-based nanocomposites reinforced with multi-walled carbon nanotubes were produced by mechanical milling followed by pressure-less sintering at 823K under vacuum. The interface between Al matrix and the multi-walled carbon nanotubes was examined using transmission electron microscopy. These observation showed that the multi-walled carbon nanotubes were not damaged during the preparation of the nanocomposite and that no reaction products were detected after sintering. The mechanical properties of sintered nanocomposites specimens were evaluated by a compression test. The yield stress (σ y) and the maximum strength (σ max) obtained were considerably higher than those reported in the literature for pure Al prepared by the same route. The values for σ y and σ max increase as the volume fraction of multi-walled carbon nanotubes increases. The milling time and the concentration of multi-walled carbon nanotubes have an important effect on the mechanical properties of the nanocomposite. [Copyright &y& Elsevier]

Graphene can be considered as an ideal reinforcement for the production of composites due to its outstanding mechanical properties. These characteristics offer an increased opportunity for their study in the production of metal matrix composites (MMCs). In this research, the studied composites were produced by mechanical alloying (MA). The employed milling times were of 1, 3 and 5 h. GNPs were added in 0.25, 0.50 and 1.0 wt% into an aluminum powder matrix. Milled powders were cold consolidated and subsequently sintered. Composites were microstructurally characterized with Raman spectroscopy and electron microscopy and X-ray diffraction. The hardness behavior in composites was evaluated with a Vickers micro-hardness test. A homogeneous dispersion of graphene during MA and the proper selection of sintering conditions were considered to produce optimized composites. The obtained results with electron microscopy indicate a homogeneous dispersion of GNPs into the aluminum matrix. Analyses showed GNPs edges where the structure of the graphene layers conserved after MA is observed. [ABSTRACT FROM AUTHOR]