Enhanced mechanical properties of friction stir welded dissimilar Al–Cu joint by intermetallic compounds

Aluminum and copper plates were successfully friction stir welded by offsetting the tool to the aluminum side, producing excellent metallurgical bonding on the Al–Cu interface with the formation of a thin, continuous and uniform Al–Cu intermetallic compound (IMC) layer. Furthermore, many IMC particles were generated in the nugget zone, forming a composite structure. Tensile tests indicated that the FSW joint failed in the heat-affected zone of the aluminum side with the Al–Cu interface bonding strength being higher than 210 MPa.