Effects of forging temperature and velocity on nano-forming process using molecular dynamics simulation

The nanoforging process of a pure copper nanorod (workpiece) is studied using molecular dynamics (MD) simulations based on embedded atom method (EAM) potential. The effects of the forging temperature and the forging velocity are evaluated in terms of molecular trajectories, pressure, internal energy, and a radial distribution function. The simulation results clearly show that the internal energy of the workpiece and the pressure exerted on it during the forging process decrease 50% and 7% with increasing forging temperature from 300 to 620 K; however, the internal energy and pressure increase 207% and 20% with increasing forging velocity from 50 to 90 m/s, respectively. During the forging process, a special atomic structure in (1 0 1) and ( 1 ¯ 0 1 ¯ ) slip planes was observed, and that represents the site of generation of dislocation and growth nucleation. When severe plastic deformation occurs, the high-energy atoms in the workpiece are significantly distributed along the direction of the slip plane due to the packing of defect structures. When the forging velocity increases, the density of the workpiece becomes more nonuniform. The forged workpiece has similar distributions of atomic density after the elastic recovery for various forging temperatures and forging velocities.