Nb含量对Cu-Ni-Nb合金组织与熔点及导热性能的影响

Effects of Nb Content on Structure,Melting Point and Thermal Conductivity of Cu-Ni-Nb Alloy

采用真空电弧熔炼工艺制备了Cu-Ni-Nb合金,研究了Nb含量对Cu-Ni-Nb合金组织、合金熔点及热导率的影响。结果表明,Cu-Ni-Nb合金基体为Cu0.81Ni0.19,第二相为NbNi3;当Ni、Nb质量比为(6~10)∶1时,Cu-Ni-Nb合金第二相形态全部为片状;当Ni、Nb质量比为(2~4)∶1时,Cu-Ni-Nb合金第二相为片状和球状。随着Nb含量的增加,Cu-NiNb合金基体中Ni原子固溶度降低,合金熔点下降,而热导率提高。Cu-20Ni-5Nb合金第二相为细小的片状和球状,均匀分布在基体中,第二相体积分数为19.2%,合金熔点为1 134.92℃,热导率为45.25 W/(m·K),可满足铸Cu冷却水套的制造和使用要求。

Cu-Ni-Nb alloy was fabricated by vacuum arc melting.The effects of Nb content on microstructure,melting point and thermal conductivity of Cu-Ni-Nb alloy were investigated.The results show that the Cu-Ni-Nb alloy is composed of Cu0.81 Ni0.19 matrix and the second phase of NbNi3.When the mass ratio of Ni/Nb is（6~10）∶1,the second phase morphology in the Cu-Ni-Nb alloy exhibits all lamellar structure.When the mass ratio of Ni/Nb is（2~4）∶1,the second phase morphology in Cu-Ni-Nb alloy presents the mixed structure of lamellar and particle structure.With the increase of Nb content,the solid solubility of nickel atoms in Cu-Ni-Nb alloy is decreased,so the melting point of the alloy is decreased,while the thermal conductivity is increased.The second phase in the Cu-20 Ni-5 Nb is fine lamellar and particle structure,which are distributed uniformly in the matrix.The second phase volume fraction reaches 19.2%,and the melting point of Cu-20 Ni-5 Nb alloy is 1 134.92℃ with its thermal conductivity up to 45.25 W/（m·K）,which can meet the requirements of manufacture and application of cast copper cooling water jacket.