Molecular dynamics simulation of diffusion bonding of Al–Cu interface

The effects of temperature on diffusion bonding of Al–Cu interface have been investigated by using molecular dynamics (MD) technique with the embedded atomic method (EAM) potentials. The simulated results indicate that the Cu atoms predominantly diffuse into the Al side in the process of diffusion bonding, and the thickness of the interfacial region depends on temperature, with higher temperatures resulting in larger thickness. In the course of diffusion bonding, the interfacial region became disordered. In addition, the Cu atoms diffuse at low ratios but can deeply diffuse into the interior of Al, and the Al atoms diffuse at high ratios but hardly diffuse into the interior of Cu. The results show that the appropriate temperature range for diffusion bonding of Al–Cu interface is 750–800 K, and the diffusion activation energies of Al and Cu are 0.77 eV and 0.50 eV, respectively. Finally, in this work, three diffusion mechanisms of Cu atoms in Al lattice have been found and the main diffusion mechanism is the nearest neighbor hopping mechanism.