(Session 11A)Microstructure and mechanical properties of friction stir welded dissimilar Al-Cu thin plate joints

摘要

Thin plates of 1060 Al alloy and commercially pure Cu (T1) were friction stir welded (FSWed) under various parameters. The experimental results revealed that many intermetallic compound (IMC) particles dispersed in the nugget zone (NZ), forming a composite structure. At a lower rotation rate of 600 rpm, the Al-Cu interface was characterized as a thin, continuous and uniform IMC layer with a thickness of about 300 nm; however, very thick layered structure of ~50 μm formed at a higher rotation rate of 1000 rpm, which mainly consisted of Al-Cu IMCs. Sound FSW joint with a high ultimate strength of 130 MPa can be achieved at the lower rotation rate of 600 rpm with a welding speed of 100 mm/min, and the joints fractured at the heat affected zone of Al side. However, the joints fractured at the NZ or the interface with clearly decreased strength as increasing the rotation rates to 800 and 1000 rpm, which is due to the formation of excessive Al-Cu IMCs. This study indicates that controlling the IMC content in the NZ and the Al-Cu interface is the key factor of achieving sound FSW dissimilar Al-Cu joints.