Continuous drive friction welding and post welding heat treatment of 7A04 aluminum alloy and 304 stainless steel

The 7A04 aluminum alloy and 304 stainless steel dissimilar materials are welded by continuous drive friction welding, and the joints were annealed at different temperature and different time. The burr morphology, tensile strength, fracture morphology, microstructure and micro-hardness of joints were analyzed. Using the appropriate process parameters can obtain good shape of the edge fin and better tensile strength, the microstructure of aluminum alloy of weld zone is dynamic recrystallization, grain refinement, and the structure is more dense than the substrate, element diffusion occurs on both sides of the bonding surface, the microhardness of weld zone is higher than that of the substrate. The tensile strength of the joints treated by 400℃×3 h annealing is obviously improved, different intermetallic compounds were formed at the interface, diffusion layer thickness increased slightly, the microhardness decreased.