Solidification During Casting of Metal-Matrix Composites

Abstract

Metal-matrix composites (MMCs) are engineered combinations of two or more materials in which reinforcing phases are dispersed in a metal or an alloy. Structurally, cast MMCs consist of continuous or discontinuous fibers (designated by the subscript f), whiskers (w), or particles (p) in a metal or an alloy that solidifies in the restricted spaces between the reinforcing phase (or phases) to form the bulk of the matrix. There are several cast materials, such as aluminum-silicon alloys and cast irons, that exhibit two-phase microstructure in which the volume and shape of the phases are governed by phase equilibria and that have a long history of foundry production. Modern cast MMCs differ from these traditional materials in that any selected volume, shape, and size of reinforcement can be introduced into the matrix, even beyond the permissible limits presented by the phase diagrams. One entry of 6061 in a table. One entry of 6061 in a table.