额外纯Cu对Cu-Nb复合线材力学及导电性能的影响

通过拉伸试验和四点测电阻法,对中心含额外纯Cu的Cu-Nb复合线材的力学及导电性能进行测试,并利用SEM观察其微观结构和断口形貌。结果表明:从断口中心到边沿,断裂方式从正断逐渐转向剪切断裂。中间纯Cu有利于导电性和强度的优化。线材的强度随着Nb芯丝间距的减小呈指数上升趋势。当间距小于100 nm时,尺寸效应对强度有显著影响,且77 K下强度随间距减小而增大的速度大于室温下强度随间距减小的速度。而当间距大于300 nm时,尺寸效应对强度的贡献很小。

Effect of Extra Cu on the Strength and Conductivity of Cu-Nb Microcomposite Wires

Mechanical strength and electrical conductivity of Cu-Nb microcomposite wires with Cu core were investigated by tensile tests and resistivity measurements. Microstructure and fracture were examined by scanning electron microscopy. The results show that the fracture mode changes from normal fracture to shear fracture from the fracture core to the edge. The additional Cu core optimizes the conductivity and strength. The strength of deformed wires increases greatly with the decreasing of Nb filament spacing by a power law. Obvious size effect shows up when the spacing is below 100 nm. At the same time, the strength increases faster at 77 K than that at RT with decrease of spacing. When the spacing is above 300 nm, the size effect is slight for the strength.