This book describes the investigations carried out on base Al6061 alloy, Al6061-WC MMCs and Al6061-WC-Gr MMHCs. The composites were developed by liquid metallurgy technique via stir casting technique. The investigations related to the Physical, Mechanical and Tribological properties along with the Optical studies on the composites both in the as-cast and heat treated conditions, before and after testing were presented and discussed.