Molecular Dynamics Simulation of Surface Effect on Tensile Deformation of Single Crystalline Copper

Based on molecular dynamics method, the tensile process of single crystalline Cu nanorod and single crystalline Cu bulk were simulated at atomic scale. The motion of atoms, total energy of atom-strain curves and number of dislocation atom-strain curves during the tensile process were acquired. The results shown that surface effect has a significant effect on the tensile mechanical properties of single crystalline Cu nanorod. For single crystalline Cu nanorod, the energy of atoms in the edges and surface were higher than the energy of atoms inside the nanorod. Dislocations nucleation in the edges that with high energy and extend along the {111} crystal plane. The nanorods produce plastic deformation and shows excellent ductility under the "dislocation nucleation-energy rising and dislocation layers cross-slip" mechanism of the alternating cycle. For single crystalline Cu bulk, dislocation nucleation randomly and extend to the entire simulation model along the {111} crystal plane quickly. The single crystalline bulk Cu produce fracture under the "microscopic vacancy-microscopic hole-penetration of microscopic holes-fracture" mechanism.