Abstract: Cu-xNi-3Ti-0.1Zr (x=2, 4, 6) alloy was prepared by vacuum melting and homogenizing annealing, hot rolling, solution treatment, cold rolling and aging treatment. The precipitates of the alloy were characterized and analyzed by means of X-ray diffractometer, optical microscope and scanning electron microscope. The results show that the addition of Ni can significantly increase the electrical conductivity of the alloy, and the effect on the hardness is also obvious. Ni exists mainly in CuNiTi phase in the Cu-xNi-3Ti-0.1Zr alloys; The addition of Ni leads to the precipitation of a large amount of CuNiTi phase in the alloy, which decreases the dissolving degree of Ti in the solid solution matrix and reduces the degree of lattice distortion of the alloy, thus increasing the electrical conductivity. However, with the precipitation of Ti element, the strengthening effect of Ti on the alloy is weakened, which leads to the decrease of the hardness of the alloy. The peak hardness of the Cu-xNi-3Ti-0.1Zr (x=2, 4, 6) alloys aged at 500 ℃ is 295, 231 and 201 HV0.5, respectively.

Key words: Cu-Ni-Ti-Zr alloy, CuNiTi phase, microstructure, hardness, electrical conductivity