Abstract
Towards sustainable societies, there is a demand for multi-material structures that utilize aluminum, which has high electrical conductivity, is lightweight, and is easy to recycle. To produce multi-material structures, the challenge to overcome is to develop a low-cost and versatile aluminum dissimilar metal joining technology. We previously proposed a technology for bonding aluminum and copper by generating and discharging a molten eutectic in less than 1 second using current and pressure in an atmosphere. However, the kind of bonding process used in this method is not clear. In this study, we conducted a bonding experiment using the eutectic reaction between aluminum and copper by applying current and pressure and evaluated the bonding behavior when bonding occurs in a short time. As a result, it was found that the molten eutectic was generated and discharged within 0.35 s from the start of energization, and by continuing this behavior for 0.3 s, it was possible to obtain a bonding strength that would cause the base material fracture (joint efficiency 85-99%). The bonding strength required for base material fracture requires an interface temperature of 548℃ or higher, which is the eutectic temperature (548℃), and the appropriate interface temperature was approximately 600℃. We clarified the relationship between high-speed eutectic reaction behavior and bonding conditions, and confirmed the usefulness of bonding methods that utilize short-time eutectic reactions.
