Abstract
The mechanical alloying was carried out using pure electrolytic copper, amorphous boron and graphite powders as starting materials, and the solid solutions or ultra fine mixtures of Cu-B-C system were obtained. These powders were altered to a boron carbide-dispersion-strengthened copper by the subsequent heat-treatment in a vacuum below the temperature of 1323 K. The mean particle sizes of B4C precipitates are about 100-300 nm. The hardness values of B4C-dispersion-strengthened coppers increased with volume percentage of B4C. In the alloy with constant volume percentage of B4C, the maximum hardness value was obtained by the heat-treatment at 873 K. The separation of copper from the boron carbide-dispersion-strengthened copper did not take place by heat-treatment at 1323 K for 7.2 ks, so the present boron carbide-dispersion-strengthened copper is excellent in thermal stability than other particle-dispersion-strengthened coppers.
