Evolution of grain structure, intermetallic compound and mechanical properties of AA6061-T6 Al/C11000 Cu dissimilar joints fabricated by friction stir welding

The grain structure evolution, interfacial intermetallic compound (IMCs) and its effects on the mechanical properties of the Al/Cu friction stir welded (FSW) joints were systematically investigated, enriching and improving the understanding of Al/Cu FSW. The Al/Cu weld was dense and well-formed under optimal welding parameters. A number of Cu particles were dispersed throughout the Al matrix, forming an Al-based composite structure. Due to dynamic recovery and dynamic recrystallisation, the grains in the WNZ of both the Al and Cu sides were refined. The interfacial reaction layer was composed of three continuous IMC layers, including Al 2 Cu, AlCu and Al 4 Cu 9 . The maximum tensile strength and elongation of Al/Cu joint reached 178.6 MPa and 5.3%, respectively.