Correlation of the mechanical properties of Cu/C composite materials with the chemistry of CuC interfacial zone

In the frame of thermal management applications, copper metal matrix reinforced by carbon fibers (CF) are undoubtedly one of the most promising composites for heat sinks. In this work, two types of composite materials were produced: Cu(CuTi)x/CF composites fabricated with a mixture of Cu and CuTi powders by a solid-liquid co-existent phase process and Cu/CF composites fabricated without the CuTi powder. The mechanical properties and post-deformation microstructures of both composite materials have been investigated. Compression tests were performed at room temperature under constant strain-rate deformation condition. Elastic properties were examined using a dynamic resonant method over the temperature range 20 °C - 250 °C. The results show that the addition of Ti and the resulting formation of the TiC interphase at the Cu-CF interfaces are able to create strong interfacial bonding evidenced by a deformation without pull-out. When the volume fraction of CFs reaches 40%, crack percolation occurs in the Cu(CuTi)/CF composite leading to the sample ruin in case of strong interfaces. In the case of Cu/CF, fiber pull-out allows for deformation.