Abstract
Weak interface bonding inhibits high thermal conductive potential of diamonds in metal matrix composites reinforced with diamond particles (Cu/diamond composites). With an attempt to modify the Cu/diamond interface, we combine Cr pre-coating and Cr alloying to produce Cu-Cr/Cr-diamond composites by gas pressure infiltration. High resolution transmission electron microscopy (HRTEM) results reveal that Cr pre-coating on the diamond surface before infiltration promotes the formation of highly active graphite-like structures. These structures enhance the interfacial reaction and intensify the formation of a uniform and dense carbide layer on the diamond surface. By altering the Cr concentration in the Cu-Cr alloy matrix, the thickness of interfacial carbide layer is tailored. As a result, a maximum thermal conductivity of 810 W m-1 K-1 is achieved in the Cu-0.5 wt%Cr/Cr-diamond composite, which is the highest value among Cr-modified Cu/diamond composites reported so far. The high thermal conductivity is attributed to optimal interface conditions: moderate thickness of interfacial carbide layer, uniform and dense carbide layer on the diamond surface, and crystallographically aligned interfacial graphite layers. This study offers a new route to modifying interface bonding and to enhancing thermal conductivity of Cu/diamond composites.
Published Version
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