Diffusion-bonding behavior of 2A97 Al-Li alloy using nano-Cu interlayer: Molecular dynamics simulation and experimental study

During diffusion bonding of Al-Li alloys, the dense oxide layer limits joint quality. Using a nano-Cu interlayer can inhibit interfacial oxidation, but its mechanism is unclear. This study combines molecular dynamics simulation and experiment to investigate the diffusion-bonding behavior of 2A97 Al-Li alloy using a nano-Cu interlayer. Results show that the nano-Cu layer promotes element diffusion, with higher temperatures enhancing the effect. At 480–500 °C, oxides and continuous Cu intermetallics in the bonded interface hinder diffusion. At 520 °C, oxides and intermetallics decrease and disperse, allowing interfacial atoms to achieve sufficient diffusion. At 540 °C, coarsening of Cu-containing intermetallics reduces mechanical properties. Simulation matches experiments, providing a theoretical basis for nano-Cu interlayers in Al-Li alloy diffusion bonding.