Microstructural evolution of Cu-10at%C nanocomposite powder during high energy mechanical milling

Abstract

The microstructural evolution of Cu-10at%C nanocomposite powder during high energy mechanical milling (HEMM) of Cu/graphite powder mixture was studied. It was found that the efficiency of milling in refining the microstructure of the copper matrix was very high with the presence of graphite in the Cu/graphite powder mixture. The average grain size of the Cu matrix reaches its minimum value of about 30 nm just after milling for 6 h, and the graphite particles were refined down to about 10∼20 nm after milling for 24 h. It envisaged that the refining of graphite particles down to 10 nm would be accompanied by formation of nanograins of copper matrix, and it appears that high energy mechanical milling can greatly enhance the solubility of carbon in copper though it is very hard to determine the exact solubility.