Graphite fiber/copper composites with near-zero thermal expansion

Mesophase pitch-based graphite fibers (MPGF) were coated with copper by electrodeposition. Subsequently, unidirectional MPGF/Cu composites with near-zero thermal expansion were fabricated by hot-pressing using copper-coated fibers as raw materials. The composites had coefficient of thermal expansion (CTE) of 0.027 × 10−6/K in the longitudinal direction which was much lower than that estimated by Sharpery’s model. Detailed thermal expansion behavior of the composites in the temperature range of 298–773 K was also studied. The endothermal/exothermal of the composites during heating was analyzed with differential scanning calorimetric (DSC). According to the results, it was considered that the zero thermal expansion behavior is related to the creep of copper matrix. The composites had thermal conductivity of 221.9 W/m K in the longitudinal direction and 42.30 W/m K in the transverse direction.

► Graphite fiber/copper composites with high fiber volume are prepared by hot-press.
► MMC60%/65% exhibit zero-expansion behavior in the temperature rang of 25–500 °C.
► Thermal conductivities of the composites are above 190 W/m K in the axis direction.