Ultrasonic welding has been accomplishing as a popular joining method in the field of electrical and electronics components owing to its capability of making good quality similar and dissimilar joints in an extremely short duration consuming very less power. The present work investigates the effects of welding energy on the mechanical, thermal and microstructural characteristics of the weld joint. The ultrasonic welding is performed on 0.36 mm thick phosphor bronze (UNS C51100) sheets. It is observed that the values of peak interface temperature and tensile-shear strength increase with the welding energy. The failure mode changes from interfacial to nugget pull-out at considerably high energy level during the tensile-shear load test. There is a significant rise in the tensile-shear load initially but negligible change is observed in the last stage. The microstructural analysis using scanning electron microscope (SEM) has revealed that the joining line appears almost straight at low energy level but fades away at higher energy level. The bonding region ultimately acquires the shape of a wavy convoluted interface. Micro-bonding accompanied by interlocking is observed as the primary joining mechanism at high energy level.

超声波焊接已成为电气和电子元件领域中一种流行的连接方法，因为它能够在极短的时间内以非常低的功耗制造高质量的相似和不同的接头。目前的工作研究了焊接能量对焊接接头的机械、热和微观结构特性的影响。超声波焊接在 0.36 毫米厚的磷青铜 (UNS C51100) 板上进行。观察到峰值界面温度和拉伸剪切强度的值随着焊接能量的增加而增加。在拉伸剪切载荷试验期间，失效模式在相当高的能量水平下从界面变为熔核拔出。最初的拉伸剪切载荷显着增加，但在最后阶段观察到的变化可以忽略不计。使用扫描电子显微镜 (SEM) 进行的微观结构分析表明，连接线在低能级时几乎是笔直的，但在高能级时会逐渐消失。粘合区域最终获得波浪状回旋界面的形状。伴随着互锁的微键合被观察为高能级的主要连接机制。