High thermal conductive diamond/Cu–Ti composites fabricated by pressureless sintering technique

Diamond/Cu composites fabricated via the traditional powder metallurgy method show low thermal conductivities due to the poor wettability between diamond and Cu matrix. The fabrication method adopted in this study provides a simple and low-cost method for producing diamond/metal composites. Thermal properties of the diamond/Cu–Ti composites fabricated by pressureless sintering at 1373 K for 30 min with variation in diamond particle sizes and volume fractions were thoroughly investigated. The composites produced in this study exhibited thermal conductivity as high as 608 W/m K for 60 vol.% bimodal diamond/Cu-2 at.% Ti composite comprised of 50 vol.% diamond particles with the size of 300 μm and 10 vol.% diamond particles with the size of 150 μm. A suitable coefficient of thermal expansion of 5.4 × 10−6 1/K was obtained. This thermal conductivity value comes up to 92% of the thermal conductivity calculated by Hasselman and Johnson model combining with diffuse mismatch model. The predicted value from this model is in good agreement with the experimental value. Furthermore, the pressureless sintering is a simple technique that requires only low-cost equipment, making this cost-effective method attractive for metal matrix composite fabrication.