工艺参数对Cu/Al大功率超声波焊接微观组织和力学性能的影响

Influence of process parameters on microstructure and mechanical properties in high power ultrasonic welding of Cu/Al

尽管大功率超声波焊接可以更好的焊接较高的导电、导热性的材料,但是对焊接机理的认识还很少.为了深入明晰焊接过程以及得到高质量的Cu/Al焊接接头,研究了不同夹紧力、焊接时间、焊接振幅以及焊头形状对Cu/Al大功率超声波焊接的界面温度、中间相生长和接头力学性能的影响.结果表明,随着夹紧力的增大,界面中间相厚度先增大后减小.随着焊接振幅的下降,界面温度的降幅增大且中间相厚度呈现近似线性下降.最优的焊头齿数为9个,焊头齿数的增多和减少均会导致界面温度降低和焊接裂纹产生.为获得较高的Cu/Al大功率超声波焊接质量,焊接振幅应设置为最高.对焊接接头的拉伸断口进行扫描电镜测试表明,Cu/Al超声波焊接接头的断裂模式是韧性-脆性复合断裂.研究结果为优化超声波焊接工艺参数提供了指导.

Although high power ultrasonic spot welding(USW) can obtain better welding quality about highly conductive materials, the welding mechanism is still unclear.To improve the understanding of the USW process and to enhance the weld strength in similar Cu/Al welding, the effect of clampling force, welding time, vibration amplitude and profile of the sonotrode tips on the temperature rise,intermetallic compound(IMC) growth of welding interface and mechanical properties of joint during Cu/Al high power ultrasonic welding process are investigared. Increasing of clampling force, the thickness of the IMC first increases and then decreases. The interface temperature decreases and the thickness of the IMC decreases linearly with vibration amplitude. The optimal number of welding head teeth is 9.Increasing and decreasing the number of sonotrode teeth will lead to lower interface temperature and formation of welding cracks. In order to obtain high welding quality of Cu/Al joint,the vibration amplitude sholud be set to its maximum.Scanning electron microscopy(SEM) test is performed on the fracture of the Cu/Al joint and shows that the fracture of Cu/Al ultrasonic welded joint is ductile-brittle hybrid mode. The research results provide guidance for optimizing the ultrasonic welding parameters.