PORTEFEUILLE

The aim of this project is the development of nanoparticulate-reinforced metals for fabrication of structural parts. Because of its unique properties, carbide-based nanopowders can enhance the mechanical performance of metal alloys. To achieve this goal, a uniform dispersion of nanopowders in the metal matrix is necessary, but agglomeration is a current issue. Nanoparticles with sizes in the range 20-30 nm will be processed by a plasma process. The feasibility of obtaining a uniform dispersion of nanoparticles in a metal matrix by high energy ball milling will be assessed. This technique produces metal-ceramic composite powders, which will be shaped by compaction and sintering. Alternative net-shaping techniques as Metal Injection Moulding and Rapid Prototyping will be investigated to obtain parts of complex geometry from the composite powders. The composite microstructure and the mechanical properties will be characterized and optimized.

The increasing demand of high strength and temperature resistant components is a driving force behind the search for advanced materials, which usually have to work on aggressive environments. The Gebert Rüf Stiftung supports this project because of the need of establishing appropriate processing conditions for nanoparticulate dispersion strengthened materials, in the perspective of potential applications in micromechanics, luxury goods, and sensors industries among others.

Successful production of carbide nanoparticles has been performed by using inductively coupled plasma synthesis. These nanoparticles have been incorporated as a reinforcement in aluminium-based powders by milling in high energy mills. Simple shape parts have been produced with the milled composite powders by hot compaction in uniaxial presses. A significant improvement in hardness has been obtained. In addition, complex geometry parts have been manufactured by injection moulding of both alloy and composite powders with appropriate binders. Dense, ductile parts with improved hardness have been obtained by the use of appropriate sintering aids. Experimental watch bracelet segments have been produced with both unreinforced alloy and nanocomposites. The aspect of net-shape parts has been improved by appropriate surface finishing.

This project has been a necessary exploratory step, and the feasibility of the main involved topics has been assessed. A solid know how has been acquired. The participant laboratories are now ready to launch new projects with the industry for the development of nanocomposite products processed by both classical and advanced powder metallurgy techniques.

«Nano-silicon carbide reinforced aluminium composites prepared by high-energy milling and hot consolidation», Kollo L., Bradbury C.R., Veinthal R., Jaeggi C., Carreño-Morelli E., Leparoux M., Materials Science and Engineering A528, 2011, pp. 6606-6615;
«Strengthening of aluminium with dispersed nanoparticulate materials by high energy milling», Leparoux M., Bradbury C. R., Kwon H., Rodríguez-Arbaizar M., Carreño-Morelli E., Kollo L., Gomon J. K. Proc. of Matériaux 2010, Nantes, France, October 18-22, 2010, pp. 1-5;
«Net-shape Al6061/SiC nanocomposites by powder injection moulding», Rodríguez-Arbaizar M., Hamdan H., Leparoux M., Kollo L., Kwon H., Carreño Morelli E. Proc. of PM2010 Powder Metallurgy World Congress PM2010, Florence, Italy, October 10-14, 2010, vol.4, pp. 429-434;
«Hardness of hot consolidated Al-SiC nanocomposites from planetary milled powders», Kollo L., Leparoux M., Bradbury C. R., Kommel L., Carreño-Morelli E., Rodríguez-Arbaizar M., Proc. of PM2010 Powder Metallurgy World Congress PM2010, Florence, Italy, October 10-14, 2010, vol.1, pp. 341-346;
«Investigation of planetary milling for nano-silicon carbide reinforced aluminium metal matrix composites», Kollo L., Leparoux M., Bradbury C., Jäggi C., Carreño-Morelli E., Rodriguez-Arbaizar M., Journal of Alloys and Compounds 489, 2010, pp.394-400.

RSR web page with short description:
http://www.rsr.ch/#/la-1ere/programmes/impatience/3053783-poudre-a-fritter.html
MP3 file can be downloaded at:
http://isi.hevs.ch/fs/documents/caf_impaticence_20110404_Poudre_a_fritter_web.mp3