An Al Alloy-Ti Microfilament Composite Manufactured by Co-Spray Forming

A. KELLY; J. MI; G. SINHA; P. KRUG; F. CROSA; F. AUDEBERT; P. GRANT

Congreso; ICAA 12 - 12th International Conference on Aluminium Alloys,; 2010

Spray forming with co-injection of a solid particulate phase to form a homogeneous distributionwithin the final spray formed billet has been studied as a new route to manufacturing metal-metalcomposites at large scale with negligible oxide. 12wt% Ti particles were co-injected into an atomised Al alloy droplet spray and co-deposited to form a 300kg billet at Peak Werkstoff GmbH, Germany.The microstructure comprised refined equiaxed á-Al grains (~5um), spherical Si particles (~1um) and uniformly distributed Ti particles (~80um). Sections of the billet were extruded under a range of conditions into long strips 20mm wide and 6mm, 2.5mm and 1mm thickness. At high strains, the Ti particles were deformed into continuous fibres of a few microns in thickness. The large interfacial area between the fcc á-Al and hcp Ti inhibited dislocation motion and enhanced tensile properties.Accumulative roll bonding was then performed to higher total strains, while maintaining a constantcross-section, reducing the Ti fibres to sub-micron thickness. The fibres were studied by extraction after selective dissolution of the á-Al matrix. There was no interfacial reaction between á-Al and Ti or any measurable oxide formation.