Investigation of easy separation of A1050 aluminum / SS400 steel joints using foaming by applying a foaming agent to the joining interface

In recent years, joining technologies have been developed owing to multi-materials. From the viewpoint of recycling, separating the joined materials is necessary when they are disposed. Our previous study of joining steel and aluminum plates showed that easy separation by foaming the joining area at the time of disposal is effective. Still, it could not be applied to a single aluminum plate. In this study, we attempted to use the foaming agent to the joining interface before FSW of steel and aluminum plates so that it could be applied to a single aluminum plate. Thereafter, the welding surface was foamed by heating. As a result of four-point bending tests, it was found that the fracture load required to fracture the specimen can be reduced by foaming the welding surface compared with those of the nonporous specimens or only heated specimens.