Title: Fabrication and characterisation of ultrafine-grained Al-5vol%Al₂O₃ nanocomposite

Authors: Z. Razavi Hesabi, A. Simchi, S.M. Seyed Reihani, F. Simancik

Addresses: Department of Materials Science and Engineering, Sharif University of Technology, P.O. Box 11365-9466, Azadi Avenue, 14588 Tehran, Iran. ' Department of Materials Science and Engineering; and Institute for Nanoscience and Nanotechnology, Sharif University of Technology, P.O. Box 11365-9466, Azadi Avenue, 14588 Tehran, Iran. ' Department of Materials Science and Engineering, Sharif University of Technology, P.O. Box 11365-9466, Azadi Avenue, 14588 Tehran, Iran. ' Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Racianska 75, 831 02 Bratislava 3, Slovak Republic

Abstract: Nanocrystalline Al-5vol%Al₂O₃ nanocomposite was synthesised by mechanical milling of a mixture containing nanometric alumina with an average particle size of 35 nm. Morphology of as-synthesised powder was investigated by SEM while crystallite size of Al matrix was determined by XRD analysis. The results confirmed formation of nanocrystalline Al matrix induced by severe plastic deformation during mechanical milling. Nanocomposite bars were produced by hot powder extrusion route. TEM investigation of as-extruded nanocomposite revealed formation of elongated grains along the extrusion direction decorated by alumina nanoparticles. Tensile and compressive properties of as-extruded nanocomposite were measured and compared with those of monolithic Al. The results show a significant increase in the strength of Al due to ultrafine-grained structure coupled with the nanoparticles induced strengthening mechanisms.

Keywords: nanocrystalline nanocomposites; metal matrix nanocomposites; Al-Al2O3; mechanical strength; nanotechnology; plastic deformation; mechanical milling; hot powder extrusion; ultrafine grain structure; aluminium; alumina.

DOI: 10.1504/IJNM.2010.033877

International Journal of Nanomanufacturing, 2010 Vol.5 No.3/4, pp.341 - 351

Published online: 02 Jul 2010 *

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