Effects of Solid Solution Temperature on Microstructure and Properties of Cu-Ni-Si-Co Alloy

Cu-Ni-Si-Co alloy ingot of φ100 mm was prepared by vacuum melting, and the alloy was solution-treated at different temperatures. The properties and microstructure of the alloy were analyzed by Brinell hardness tester, eddy current conductivity instrument, metallographic microscope and scanning electron microscope. The results show that the second phase of the as-cast Cu-2.25Ni-0.6Si-0.3Co alloy is a Ni₂Si compound with a size of 1-2 μm and a relatively small aspect ratio,increasing the contents of Ni, Si and Co, the size and aspect ratio of the second phase of the alloy are increased, and it is formed into a（Ni, Co）₂Si compound with a size of 3-5 μm. With the increase of the solution temperature, the hardness of the alloy first decreases, then increases and decreases, the conductivity first decreases sharply and then levels off. The solid solution effect of the alloy after 950 ℃ insulation for 1h is better. The hardness and conductivity of the two alloy samples are 90.13 HB, 20.79%IACS and 121.67 HB, 17.74%IACS, respectively, the grain sizes are（3.0±1.05） mm and（3.22±1.42） mm, respectively.