Fabrication of Al/Al<SUB>2</SUB>O<SUB>3</SUB> Particle Reinforced Metal Matrix Composite by Sheath Rolling of Powder Mixture

Abstract

An Al/Al 2 O 3 particle reinforced metal matrix composite was fabricated by sheath rolling of powder mixture. A stainless steel tube with the inner diameter of 10 mm and outer diameter of 12 mm was used as a sheath. Mixture of aluminum powder and Al 2 O 3 powder of which volume fraction was varied from 5 to 20% were filled in sheath and rolled to the reduction of thickness of 75% at ambient temperature. Rolled powder compact was sintered, and after sintering additionally rolled and annealed for improvement of mechanical properties. The powder mixture could be consolidated by sheath rolling at ambient temperature. Relative density of composite became more than 0.96. The strongest composite in the present process was obtained after additional cold rolling subsequent to sintering, while it had poor ductility. The strength and ductility of the sintered composite was improved by additional cold rolling and annealing. The strength of sintered composite and that of additionally rolled and annealed composite increased with increasing volume fraction of Al 2 O 3 particles. It became about one and a half times as that of unreinforced powder compact at the volume fraction of 20%. It is proved that the sheath rolling method is promising process for fabricating metal matrix composites on powder metallurgy route.