铜/铜超声波焊接的相对运动及断面微观演变

Relative motion and its relation to microstructure evolution during high-power ultrasonic welding of copper sheets

关键词:  振幅  超声波焊接  相对运动  微观演变

Key words:  vibration amplitude  ultrasonic welding  relative motion  microcosmic evolution

摘要:

采用激光位移传感器对铜/铜超声波焊接过程中的工具头、上铜板及下铜板的振动进行实时测量.依据各部分的相对运动及断面的微观演变对焊接过程进行了分析.结果表明，焊接过程中，焊头振幅变化不大，上铜板振幅先增大后减小再增大，下铜板振幅逐渐增大.上铜板振幅增大阶段，上/下铜板的相对运动使界面产生大量摩擦热，界面形成局部微连接.上铜板振幅减小阶段，焊头与上铜板的相对运动显著增大，促使铜板发生剧烈的塑性变形，焊接界面连接面积迅速增加.最后阶段，上下铜板呈等振幅运动，焊接接头断面出现大量韧窝.

Abstract:

Real time dynamic measurements on the vibration amplitude of the sonotrode, the upper and lower copper sheet were performed using laser displacement sensor during ultrasonic welding of copper sheets. The welding process was analyzed on the basis of the relative motion among three parts and the microcosmic evolution of fracture surface. The results showed that during the welding process the amplitude of sonotrode changed little and that of the lower sheet increase gradually. Meanwhile, the amplitude variations of the upper sheet progess is increased at first then decreased and increased again. In the amplitude increase stage, a quantity of friction heat were generated owing to the relative motion between the two welded sheets. Besides, the microjoining appeared at the welding interface, In the amplitude decrease stage, the relative motion between the upper sheet and the sonotrode increased rapidly. It prompted the occurrence of the severe plastic deformation and the effective bonding area increased rapidly. Finally, the upper and lower sheets vibrated at the same amplitude. A large number of dimples were observed on the fracture surface.