Graphite metal composites with tailored physical properties

Abstract

Graphite provides a good opportunity for the development of new metal matrix composites (MMCs) due to its interesting properties, including thermal conductivity, high internal damping, and low density. According to the particular application, metal–graphite composites with their tailored properties can be used in the areas of thermal management of electronic devices. Metal–graphite composites show anisotropic properties due to the orientation of the graphite flakes during consolidation. Powder metallurgical technologies can be used to manufacture composites with graphite contents up to 90 vol. %. Besides copper, other matrices were investigated like tungsten, aluminium, and iron. The thermophysical properties (thermal conductivity, thermal expansion) as well as damping properties were characterized as a function of the composition. Interesting metal–graphite composites combining tungsten and 70 vol. % graphite flakes show a thermal conductivity in two directions of 400 W/mK in combination with a physical coefficient of thermal expansion of 3·5 ppm/K and a high damping.