3. Machinability Aspects of Metal Matrix Composites

Machining of Metal Matrix Composites (MMCs) is notoriously known to be difficult due to both the presence of two or more distinct phases, one of which is very abrasive, and for the marked differences between the two constituents: the hard ceramic reinforcement and the ductile metal matrix. For this reason, a number of efforts have been made to produce metal matrix composite components in near-net-shape forms. However, such parts always have to be machined to match the final design requirements. The aim of this chapter is to give an overview of the present knowledge about the machinability of MMCs, which represents one of the most important concerns which tends to limit the number of applications of these materials in industry. After an introduction about the meaning of machinability, the main characteristics of the material, which can play a significant role on the machinability of MMCs, are presented. Such characteristics are then analysed and discussed in the subsequent sections as regards their influence on cutting tool wear, surface integrity, cutting forces and chip formation.