Influence of Aging Treatment on the Microstructure and Properties of a Deformation-Processed Cu-Ni-Co-Si Alloy

We investigated the influence of aging on the microstructure and properties of a deformation-processed Cu-Ni-Co-Si alloy. Aging caused recovery and recrystallization in the Cu matrix and the precipitation of Ni₂Si, Cu₁₅Si₄ and CoSi. At the temperature of 350 °C, increasing aging time caused the hardness to increase to a peak value at 0.5 h, and subsequently to decrease at longer aging times. At higher temperatures, the hardness decreased with increasing aging time. The conductivity and elongation to fracture increased with increasing aging time and tended to saturation at about 4 h. The hardness, conductivity and plasticity of the alloy cold rolled at 47% reduction, after the optimal aging treatments at (i) 350 °C for 0.5 h, (ii) 400 °C for 1 h, (iii) 500 °C for 0.5 h, were (i) 262 HV, 45.8%IACS and 3.6%; (ii) 249 HV, 48.1%IACS and 4.4%; (iii) 230 HV, 49.8%IACS and 5.5%, respectively. Based upon our results, we recommend the adoption of the optimized process.