Preparation and Thermal Conductivity of Copper Plated Carbon Fiber Dispersed Steel Matrix Composites

Abstract

Since the die-casting mold repeats rapid heating and cooling during operation, the defects such as heat checks generate. Therefore, the quality and the life of the mold are degraded. To improve these demerits, the improvement of the thermal conductivity of the mold material is effective. In this study, carbon fibers were added to SKD61(40CrMoV5) tool steel to fabricate the composites with high thermal conductivity. Since carbon fiber has a chemical reaction with steel, electroless copper plating was applied to carbon fiber to suppress the reaction. The composites were fabricated by the unidirectional arrangement of carbon fibers and spark plasma sintering. The results obtained are as follows. 1) Carbon fiber/SKD61(40CrMoV5) composites with a high relative density were obtained. It is considered that the copper plated on the carbon fiber acted as a sintering accelerator. Furthermore. the plated copper remained around the carbon fibers in the composite, and it seems copper prevented the direct reaction between carbon and steel. 2) The composites had higher thermal conductivity than the monolithic SKD61(40CrMoV5) block. As increasing the carbon fiber content, the thermal conductivity increases. 5vol.% copper-plated carbon fiber/SKD61(40CrMoV5) composites have a thermal conductivity of 42 W /mK.