The effects of Nb addition on the microstructures and mechanical properties of the casting Cu-9Ni-6Sn alloy were investigated in the present work. Microstructures of the as-cast and heat treated samples were characterized by optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results demonstrate that, with the addition of Nb from 0.0 wt% to 0.35 wt%, the average grain size of Cu-9Ni-6Sn alloys in the as-cast condition is reduced from 570 µm to 156 µm due to the formation of Nb-bearing intermetallic compounds. The occurrence of NbNi₃ particles after solution treatment is considered as an important factor that leads to the postponed hardening response to age treatment in the early stage. For the peak-aged samples with 0.35 wt% Nb addition, the tensile strength is increased from 768.9 to 913.3 MPa when compared to that of the Nb-free samples. In addition, for the peak-aged samples, the hardness increment is mainly attributed to the coherent stress generated by the ordered γ' phases, which results in practically identical hardness (~350 HV) regardless of the Nb additions. Furthermore, an optimized combination of UTS (719.5 MPa), elongation (13.76%) and electrical conductivity (11.37% IACS) of the Cu-9Ni-6Sn alloy can be achieved by the 0.35 wt% Nb addition accompanied with aging treatment at 375 ℃ for 1 h.

在本工作中，研究了添加Nb对铸造Cu-9Ni-6Sn合金的组织和力学性能的影响。通过光学显微镜（OM），扫描电子显微镜（SEM）和透射电子显微镜（TEM）对铸态和热处理样品的微观结构进行表征。结果表明，通过添加0.0％（重量）至0.35％（重量）的Nb，铸态条件下的Cu-9Ni-6Sn合金的平均晶粒尺寸由于形成了Nb而从570 µm减少至156 µm。轴承金属间化合物。NbNi ₃的发生固溶处理后的颗粒被认为是导致早期时效处理延迟硬化反应的重要因素。与不含Nb的样品相比，添加0.35 wt％Nb的峰值时效样品的拉伸强度从768.9 MPa增加到913.3 MPa。此外，对于峰值时效样品，硬度增加主要归因于有序γ'相产生的相干应力，无论添加Nb多少，硬度实际上都相同（〜350 HV）。此外，通过添加0.35 wt％的Nb并在375℃进行时效处理，可以实现Cu-9Ni-6Sn合金的UTS（719.5 MPa），延伸率（13.76％）和电导率（11.37％IACS）的优化组合。 1小时。