不同铜线芯直径超声波焊接头性能的研究

Study on properties of ultrasonic welding joints with different copper core diameters

对3种不同的线芯直径的10 mm双铜(Cu)导线接头进行超声波焊接试验。通过剥离试验、孔隙率计算、温度测量、扫描电子显微镜(SEM)研究分析了铜导线接头性能和失效形式。结果表明:线芯直径与接头抗剥离力正相关,线芯直径越粗接头力学性能越好。两根线芯直径为0.1 mm导线焊接的接头抗剥离强度未达标,失效形式为结合面完全分离无线芯断裂。直径增至0.2 mm时,接头抗剥离强度均达到标准,失效形式变为结合面处线芯的韧性断裂。焊接时的峰值温度有效影响了接头孔隙率,但孔隙率并不能完全作为判断接头成型质量的依据,部分导线在高温下仅发生塑性变形,而未能实现原子键合。此外,通过观察接头剖面发现,焊接接头形成了外紧内松的结构,与压块接触的接头上侧和与焊头接触的接头下侧几乎无空隙,而接头中间内侧则存在大量空隙。

Ultrasonic welding tests were carried out on 3 kinds of 10 mm double copper(Cu)wire joints with different core diameters.The properties and failure modes of copper wire joint were studied by stripping experiment,porosity calculation,temperature measurement and scanning electron microscopy(SEM).The results show that the core diameter is positively correlated with the stripping resistance of the joint,and the larger the core diameter is,the better the mechanical properties of the joint are.The peeling strength of two wire welded joints with a core diameter of 0.1 mm is not up to standard,and the failure form is complete separation of the joint surface and wireless core fracture.When the diameter is increased to 0.2 mm,the stripping strength of the joint reaches the standard,and the failure form changes to the ductile fracture of the core at the bonding surface.The peak temperature during welding effectively affects the porosity of the joint,but the porosity can not be completely used as the basis for judging the forming quality of the joint.Some wires only undergo plastic deformation at high temperature,and fail to achieve atomic bonding.In addition,by observing the joint profile,it is found that the welded joint forms an outer tight and inner loose structure,and there is almost no gap on the upper side of the joint in contact with the press block and the lower side of the joint in contact with the welding head,and there is a large number of gaps in the middle of the joint.