Interfacial Bonding Mechanism of Al–Fe Dissimilar AFSD Cladding Components

Abstract Large-scale cladding of AA2024-T4 over a 1045 steel plate surface was successfully achieved by additive friction stir deposition (AFSD), and the dissimilar bonding and strengthening mechanism of the Al–Fe alloy around the interfacial region are thoroughly discussed. The results indicate that the continuous amorphous phase at the Al–Fe bonding interface replaces the crystalline intermetallic compounds (IMCs). The continuous amorphous phase prevents crack propagation during the tensile test, thereby enhancing the strength of the dissimilar Al–Fe joint, with the maximum tensile strength reaching 282 MPa. The constant strain promoted rapid interdiffusion of Al and Fe and ensured that the continuous amorphous layer did not fracture. Moreover, the rapid diffusion of Fe increased the stability of the amorphous phase, allowing the amorphous layer to remain at the interface after AFSD. This demonstrates that effective bonding between Al and Fe can be achieved without IMCs, challenging the traditional understanding. This study provides a new method for preparing large-scale ultrastrong Al–Fe composites of any thickness and solving the challenge of achieving large-scale Al–Fe bonding without IMCs.