Improvement of thermal conductivity of diamond/Al composites by optimization of liquid-solid separation process

摘要

Diamond/Al composites have been considered as the new generation of thermal management material. The critical challenge is that Al4C3 with deteriorating properties is easily generated at the interface of composites by conventional powder metallurgy and infiltration processes. This paper presents an independently developed liquid-solid separation (LSS) technology for fabricating diamond/Al composites with Cr-coated diamond particles. The key parameters of the LSS process such as the blank heating rate and its heating mode, the squeeze casting temperature and pressure, and pressurization time were optimized. Cr coating of the diamond particles led to improved interface characteristics. The higher thermal conductivity of diamond/Al composite with Crcoated diamond particles is attributed to the favorable interfacial products of Al13Cr2 and AlCr2. Thermal conductivity of 40 vol.% Cr-coated diamond particles reinforced diamond /Al composites prepared by LSS with the optimal process was 309.20 W m-1 K-1, 108.06 % higher than that of the composite without the Cr coating. The results showed that relative density is a critical factor in optimizing of the bending strength, compressive strength, and thermal conductivity of the composites. No harmful intermetallic Al4C3 is generated at the interface of the composite. LSS technology is the new low-cost and compact method for the fabrication of diamond/Al composites with high thermal conductivity, which has the prospect of industrial application.