Effects of layered structure, composition, and annealing on nanoformed Au–Cu rods using molecular dynamics simulation

The nanoforging process of gold–copper (Au–Cu) rods is studied using molecular dynamics (MD) simulations based on the embedded atom method (EAM) potential. The effects of the layered structure, composition, and annealing are evaluated in terms of atomic trajectories, internal energy, pressure, and the radial distribution function. At the initial forging stage, the deformation mechanism for Au–Cu rods with a layered structure is the formation of shear bands at the Au/Cu interface. With further compressive loading, a few atoms gradually diffuse from one layer into another layer, leading to further plastic deformation. During the forging process, the internal energy of rods, the pressure exerted on them, and filling ability increase with increasing proportion of Au atoms. After complete unloading, an elastic recovery of 9–54% occurs for forged workpieces (rods); the extent of recovery increases with increasing Au atom concentration. The magnitude and distribution of the residual strain energy significantly depends on the composition and initial structure of a rod. Annealing increases the speeds of atomic recovery and strain energy relaxation inside a forged workpiece.