Ultrasonic welding is an attractive joining method, because bonding is quickly obtained without extra heat or welding metal. Thus far, there have been several researches about the bonded interface structure and process of the ultrasonic welding. However, there were only few studies about the application of ultrasonic welding to the Al/Glass substrate and detailed bonding mechanism was unclear. In this report, ultrasonic bonded interface between an Al wire and a glass substrate was observed by high resolution transmission electron microscopy. The bonded sample was cut perpendicular to the interface and, the atomic structure and chemical composition of the cross-section of the sample were analyzed. Around the interface between Al and Glass, several dislocations and Al sub-grains were produced in Al and no intermetallic compounds were observed. Al and Glass were directly connected at the interface. This indicates that dislocations generated at the interface moved to form low angle grain boundaries during a recovery process without intermetallic formation.
