Microstructural and mechanical characterization of Al-MWCNT composites produced by mechanical milling

Novel Al-based nanocomposites reinforced with multi-walled carbon nanotubes were produced by mechanical milling. Next, pressure-less sintering at 823 K under vacuum and hot extrusion at 773 K were carried out. The interface between Al matrix and the multi-walled carbon nanotubes was examined using transmission electron microscopy. The values of yield strength (sigma(y)), maximum strength (sigma(max)) and microhardness Vickers (HVN) of the composites were evaluated and reported as a function of carbon nanotubes content. The concentration of multi-walled carbon nanotubes has an important effect on the mechanical properties of the nanocomposite. Formation of aluminum carbide in the nanocomposites was observed. Possible strengthening mechanisms are presented and discussed. (C) 2008 Elsevier B.V. All rights reserved