Effect of Thermal Treatment on Intermetallic Phases of Fe/Al Structural Transition Joints

摘要

In ship industries, the welding of aluminium and steel is an important task to perform, however it is impossible to directly weld aluminium to steel by conventional fusion welding processes. To overcome this difficulty, the Fe/Al explosion-welded structural transition joints (aluminium 5083: aluminium 1050: steel St.52-3N) is used as intermediate strip to join aluminium and steel together. In this study, the thermal sensitizing temperature of 300 °C is used to study the changes of intermetallic phases in Fe/Al structural transition strip. The techniques used for this study are: scanning electron microscopy equipped with energy dispersive spectroscopy (SEM7EDS), optical microscopy (OM), and Image Analyzer to study the microstructure's change and to quantify the amount of intermetallic phase present in the specimen. According to the obtained results, the amount of intermetallic phase precipitation (β) in the aluminium 5083 layer has significantly increased after thermal sensitizing at 300 °C for both 5 and 15 minute of heat treatment.