Optimized thermal properties in diamond particles reinforced copper-titanium matrix composites produced by gas pressure infiltration

Interface modification is crucial to exploit high thermal conductive potential of diamond in the metal matrix composites reinforced with diamond particles (Cu/diamond composites). With an attempt to modify the Cu/diamond interface, we add a carbide-forming element of Ti to the Cu matrix and use a liquid-phase processing technique to attain sound interfacial bonding. The Cu-xTi/diamond composites were characterized by using scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. The interface layer is confirmed as TiC, the amount of which increases with increasing Ti concentration in the Cu-xTi alloy matrix. As the Ti concentration increases, the thermal conductivity of the Cu-xTi/diamond composites first increases and then decreases, giving an optimized thermal conductivity of 752 W/m K and a coefficient of thermal expansion of 6.50 × 10−6/K at x = 0.5 wt.%. The results show that an appropriate amount of Ti addition in Cu matrix can enhance the thermal conductivity of Cu/diamond composites.