Development of heat balance model and thermal analysis method for interface heating in Al/Cu energization-induced high speed eutectic bonding

Toward the realization of a sustainable society, the realization of multi-material structures requires the development of low-cost, versatile aluminum dissimilar material joining technology and the development of structures suitable for a circular economy. We have established a high-speed eutectic bonding method that generates and expels eutectic at the interface of dissimilar metals in a short time, aiming to reduce costs and improve versatility, and have developed a bonding technology with a bonding strength that can fracture the base material. In this study, we developed a thermal analysis method to gain insight into a bonding judgment system for dissimilar metal bonding method using high-speed eutectic reaction. This thermal analysis method is characterized by using energization heat balance experiment model to calculate interface heat including energizing environmental factors and then perform thermal analysis. The accuracy of thermal analysis was compared based on temperature distribution of experimental values and analyzed values, using bonding conditions of multi-material structure that obtains base metal fracture strength through high-speed eutectic reaction. Error rate was about 5% within 4 mm from the interface, which is a reasonable accuracy for determining conditions for bonding by eutectic reaction, and prospects for developing bonding judgment system were obtained.