DESIGN WITH METAL-MATRIX COMPOSITES

Applications for metal matrix composites (MMCs) have not emerged at th e rate needed to justify the development costs. A reason for this may be that material developments have not been adequately linked to ident ified commercial needs. It is certainly true that some of the expectat ions raised about the potential offered by MMCs have been misguided. A s the MMC business contracts, there is an ever greater need for a syst ematic method of linking material properties to the needs of engineeri ng designers. This paper presents a methodology for evaluating materia ls in design, with the aim of linking MMCs to applications. The method ology has two main components: first, the use of performance indices a nd materials selection charts for specific design goals, to compare ex isting MMCs with competing materials; and secondly, the conceptual des ign of new MMC systems guided by those design goals. A selection of ca se studies illustrates that in mechanical application the gains in usi ng MMCs are frequently marginal, whereas in design for thermal managem ent and vibration control, the materials can show very substantial imp rovements in performance. The methodology is general, and could be app lied to other material systems. (C) 1994 The Institute of Materials.