Atomistic simulation of effects of temperature and velocity on tensile-deformed Au/Cu/Au/Cu films

The effects of temperature and tensile velocity on the mechanical properties and mechanics of Au/Cu/Au/Cu nanofilms under tensile testing are studied using molecular dynamics simulations based on the many-body embedded-atom potential. The simulation results show that at the initial tensile deformation, dislocations nucleate at layer interfaces, propagate along close-packed plane {111} toward the interior of the film, and are then terminated by layer interfaces, which act as a barrier. The proportions of atoms in face-centered cubic and hexagonal close-packed structures during tensile deformation decrease and that in other structures (disordered atoms) increases when the temperature increases from 273 to 700 K. Breaking occurs at layer interfaces at higher temperatures or tensile velocities, indicating that the interface is the weakest structure in the films. Breaking occurs earlier when a higher tensile velocity is used. The mechanical strength of the films increases with decreasing temperature and increasing tensile velocity.