Experimental and numerical studies on ultrasonic welding of dissimilar metals

Ultrasonic metal welding (USMW) is gaining popularity for joining thin and dissimilar metal sheets and foils. In the present study, a new type of booster and horn is proposed and modeled with adequate precision. The modal analysis module of finite element method (FEM) is used to analyze the effects of different step lengths and fillet radius on its natural frequency. The dynamic analysis has also been performed to find out the stress distribution in both parts under cyclic loading conditions. It enables to locate the highly stressed nodal regions (hot areas), and the relevant temperature field is consequently determined. A 0.02 and 0.008% errors have been noticed for horn and booster while comparing FEM results with the experimental values respectively. The experiments are conducted on the 0.3Al-0.3Cu specimens with the designed parts to study the effects of various controllable process parameters like vibration amplitude, weld pressure, and weld time on the tensile shear and T-peel strengths. Intermetallic compound of Al2Cu with a layer of 1.5-μm thickness has been formed for the good weld samples, and it is very much sensitive towards the parameter combinations. This paper provides an insight not only to produce high-quality welds but also to solve many industrial issues by explaining the comprehensive background theories on fatigue and vibro-thermographic analyses of the booster and horn along with detailed microscopic analyses of fractured surface.