Solid-liquid co-existent phase process: Towards fully dense and thermally efficient Cu/C composite materials

Highlights: • In-situ titanium carbide interphases were obtained using the solid-liquid co-existent phase process. • The liquid phase enhanced the diffusion of Ti towards the carbon reinforcements, thus purifying the Cu matrix. • EELS analyses confirmed the stoichiometry of the TiC interphase predicted by the thermodynamic simulations. • The thermal conductivity of the composite materials was enhanced with respect to composites with no Ti addition. Metal matrix composites are currently being investigated for thermal management applications. In the case of a copper/carbon (Cu/C) composite system, a particular issue is the lack of affinity between the Cu matrix and the C reinforcements. Titanium-alloyed Cu (Cu-Ti) powders were introduced in a Cu/C powder mixture and sintered under load at a temperature at which the Cu-Ti powders became liquid, while the rest of the Cu and C remained solid. Fully dense materials were obtained (porosity of less than 5%). The creation of regular and homogeneous interphases was confirmed. All Ti reacted with the carbon, hence purifying the Cu matrix. Thermal conductivities were enhanced as compared with the Cu/C composites without interphase. The chemical analyses are in agreement with thermodynamic simulations carried out to predict the phase transformation during the sintering process.