Abstract
Al2O3 particle dispersion strengthened Cu-Al alloys were prepared by the internal oxidation method. Three Cu-Al alloys with different Al content, namely Cu-0.44 wt% Al, Cu-0.8 wt% Al, and Cu-1.42 wt% Al, were used in this work to study the effects of Al content, cold work, oxidation temperature and time on their properties as possible leadframe materials. The Cu-Al alloys were internally oxidized by the Rhines pack method. The specimens were embedded in a mixture of Cu, Cu2O and Al2O3 powder and wrapped in a Cu foil. The weight ratio of Cu: Cu2O: Al2O3=1:2:3. After the pack was vacuum-sealed in a quartz tube, it was heated in a furnace for 8 to 32 hours at 800℃ and 900℃ to have the specimens oxidized. Compared with the commercial C194 and C7025 Cu alloys, the internally oxidized Cu alloys in this work gives superior combination of high electrical conductivity and high hardness. They also showed high softening resistance. The softening temperature of them were higher than 750℃. Among them, the Cu-0.8% Al alloys were completely internally oxidized for 16 hours at 900℃ and showed the best combination of properties of hardness, high softening-resistance and electrical conductivity. For the R-0.8% Al-900℃-16 h specimen, the properties are: hardness=156.5 Hv, conductivity=84.9% IACS and softening temperature>850℃.