Thermal properties of metal matrix composites with planar distribution of carbon fibres

High thermal conductivity (TC) and a tunable coefficient of thermal expansion are essential properties for heat management materials operating in a wide temperature range. We combine both properties in a composite with a low‐density metal matrix reinforced with pitch‐based carbon fibres. The thermal conductivity of the metal matrix was increased by 50%, the thermal expansion coefficient was reduced by a factor of five. The samples were produced by powder metallurgy and have a planar random distribution of fibres, leading to high performance in two dimensions. Surface of a metal matrix composite with 50% carbon fibre (CF) strengthening (optical microscope, 20× magnification). For the cooling of electronic components, copper is commonly used due to its excellent thermal conductivity. However, the high thermal expansion of copper might cause a mechanical failure of the cooled component. The authors present a material out of metal and carbon fibres which combines high thermal conductivity and low thermal expansion. As a side effect, this material is over four times lighter than copper.