Review of the Thermal Conductivity of Graphite-Reinforced Metal Matrix Composites

Abstract

The characteristics of graphite-reinforced metal matrix composites (MMCs) are increasingly important in a wide range of technologies. While most of the published studies deal with the mechanical properties of these materials, there have been limited studies characterizing the thermal properties of some of these materials. The effective thermal conductivity is of particular importance for design and applications, and experimental data are summarized and compared with accepted models of composite properties. On the basis of this review, it is evident that the thermal properties of graphite ber-reinforced MMCs have not been adequately investigated. Modeling techniques based on limited experimental data have identi ed some of the important parameters, but no single model adequately predicts either the longitudinal or the transverse conductivity of these materials. This study presents a review of the experimental and analytical investigations of the thermal conductivity of these materials and concludes with recommendations for emerging and continuing areas of investigation. Nomenclature a = ber radius d = ber diameter h c = ber -matrix interface contact conductance k = thermal conductivity L = longitudinal s = vertical ber separation T = transverse t = horizontal ber separation V = ber volume fraction v/o = ber volume fraction f = angle of departure from longitudinal direction of the composite Subscripts c = composite e = effective f = ber m = matrix r = radial u = circumferential '= perpendicular to ber direction // = parallel to the ber direction