The diffusion behaviors at the Cu-Al solid-liquid interface: A molecular dynamics study

The Cu-Al composite material possesses a large potential value in practical application due to its excellent properties. Whereas the Cu/Al interface is an inevitable issue to be solved both experimentally and theoretically. Thus, the effects of temperature, pressure on atomic interdiffusion along the direction perpendicular to the Cu (1 1 0)/Al solid-liquid interface have been investigated by using a molecular dynamics (MD) method with the embedded atomic method (EAM) potentials. The results indicate that the diffusion coefficients of both Cu and Al atoms layers, as well as the diffusion depth of Al atoms, satisfy Arrhenius formula with the system temperature. The diffusion depth of Cu atoms presents a linear relationship with system temperatures. While the thickness of diffusion layer presents a parabolic relation with diffusion time, which is also in good agreement with the experimental results. In addition, we show that the diffusion rate of Cu atoms diffusion in Al liquid is more than 5 times that of Al atoms diffusion in Cu layers, and sequentially the alloy layers are mainly formed by the diffusion of Cu atoms in the Al liquid. Finally, the intermetallic in alloy layers is mainly identified as theta-Al2Cu once solidification by annealing. These findings have useful in designing Cu/Al interface in practices.