Rapid pulsed current diffusion bonding of 6063 Al alloy: Electric-field-driven atomic diffusion

Pulsed current diffusion bonding (PCDB) was successfully employed for bonding 6063 Al alloy. The effects of process parameters on the interfacial microstructure and mechanical properties of the 6063 Al alloy joints were systematically investigated, and the influence of pulsed current on atomic diffusion was further explored. As the bonding temperature was increased and the holding time was prolonged, interfacial voids gradually closed, and the continuous oxide film fragmented progressively. Transmission electron microscopy (TEM) characterization revealed that the fragmented residual oxide film, in the form of nanoparticles, pinned the grain boundaries, thus hindering the cross-interface growth of recrystallized grains. The joints achieved an optimal shear strength of 71.5 MPa at 500 °C for 30 min. In contrast, traditional diffusion bonding failed to form a well-bonded interface, with its shear strength being only 15.0 MPa. Molecular dynamics simulation results indicated that the atomic diffusion coefficient under the electric field was enhanced by 46.8 % compared with that under a pure temperature field. This work holds great significance for the rapid fabrication of high-quality precision 6063 Al alloy components.