Microstructure and thermal conductivity of Cu-Cu2AlNiZnAg/diamond coatings on pure copper substrate via high-energy mechanical alloying method

Abstract

In the present work, a novel system of Cu2AlNiZnAg high entropy alloys (HEAs) powder was successfully synthesized and Cu-Cu2AlNiZnAg/diamond coatings were fabricated on T2 pure Cu substrate via mechanical alloying method. Characterization of the Cu2AlNiZnAg HEA powder indicated that a single FCC solid solution phase was formed and no indication of any amorphous phase or intermetallic compound was found in the microstructure. The FCC phase was Cu-rich phase. The coatings exhibit a microstructure composed of black particles of diamonds and gray areas of Cu2AlNiZnAg HEA reinforced Cu matrix composites. The effects of Cu-Cu2AlNiZnAg/diamond ratio and milling time on the fabrication of coatings were investigated. The effect of annealing treatment on the microstructure of coatings was discussed. The microhardness of the coating was far higher than that of copper substrate whether it was annealed or not. The thermal conductivity of the fully coated sample was improved greatly after annealing, reaching 358.53W•m−1•K−1, which was superior to the T2 pure copper with the same annealing treatment.