Development of Al/Cu Dissimilar Joint by New Friction Welding Method

Abstract

Aluminum alloy / pure copper joint has been tried to produce by the conventional welding method. However, some combination of the joints could not show high joint efficiency. The reason for this is considered to the formation of the intermetallic compound and involvement of the metal flake of joint specimens. A2017 aluminum alloy/Cu joint was examined by the new friction welding technology which has the intermediate material for friction between joint specimens. Furthermore, thermal elastic-plastic stress analysis was conducted for searching the optimum welding condition. The results are as follows. (1) 60% joint efficiency larger than that in the conventional process was obtained. (2) Intermetallic compound and involvement of the metal flake are not recognized by a micro inspection such as SEM. (3) Increase of oxygen content is recognized in Al side near the interface, however, it occurred during upset stage because oxygen content does not increase in Cu side. (4) The precise position of welding interface could be determined from the change of oxygen content near interface. (5) For producing sound joint of this combination of the materials, it is important that both materials are plastically deformed by maintaining strength balance between Al and Cu near the interface.