Fabrication of Al-4.5Cu/15SiC p composites: I. Processing using mechanical alloying

Abstract

Al-4.5Cu/15SiC p composites have been fabricated by the mechanical alloying of aluminium powder, copper powder and SiC particles using a horizontal ball mill. A desirable state of mechanical alloying can be attained after 10 hours of milling, resulting in a reduced particle size, the attainment of the highest microhardness of the powder mixtures and a nearly constant green density of the compacts produced. Compared to the conventional mixing method employed in powder metallurgy, mechanical alloying achieved a better distribution of the SiC particles as well as a good alloying of copper within the aluminium matrix. Although a slightly lower density was obtained, mechanical alloying yielded an increase in microhardness to about twice that obtained by conventional mixing. The reasons leading to these changes are enumerated and discussed in the paper.