Abstract
In this study, a process combining powder metallurgy and equal channel angular extrusion (ECAE) was developed. By a modified ECAE die based on Segal’s H plunger design, Cu and Cu + Al2O3 powder billet can be successfully extruded at room temperature to form a bulk material. The load needed during extrusion was analyzed and it is contributed mainly by adhesion friction. The Cu – 0.5 ~ 5 % Al2O3 bulk materials produced in this study reached 98% of its theoretical density in the first pass. The Cu matrix strengthened by nano-sized Al2O3 particles has a grain size of nanometer scale. The grain size of the material remains at 200 nm after annealing at 600 oC for one hour. The material shows good electrical and mechanical properties and excellent softening resistance. Hardness in the range of Hv 140 to 160 can be obtained after first extrusion. For billets that contains Al2O3 more than 0.5 wt%, hardness higher than Hv 92 and conductivity higher than 90% IACS were obtained after annealing at 400 oC for one hour. After annealing at 400 oC for one hour, less than 20 % softening could be found even further heat to 1000 oC for one hour.