Effect of Annealing Process on Microstructure and Mechanical Properties of Ultrafine Copper Prepared by Spark Plasma Sintering

The spark plasma sintering (SPS) method is used to prepare the ultrafine copper with the average grain size less than 10μm and the tensile strength greater than 280MPa. The ultrafine copper is annealed at different temperatures for 60min, and the annealing microstructure is observed and the hardness and the deformation behavior of the bulk copper are tested. The results indicate that the grains grow very slowly when the annealing temperature is less than 450℃. However, the grain growth becomes remarkable when the annealing temperature exceeds 450℃. And the plasticity of the bulk copper is the best when the annealing temperature of 450℃ is adopted. After stamping and spin forming, the deformed copper is recrystallized completely and the grain is refined when the copper is annealed at 500℃ for 30min.