Effects of voids in tensile single-crystal Cu nano-beams

Molecular dynamic simulations of defect nano-sized beams of single-crystal Cu, loaded in displacement controlled tension until rupture, have been performed. The defects are square-shaped, through-the-thickness voids of different sizes, placed centrally in the beams. Three different cross section sizes and two different crystallographic orientations are investigated.

As expected, the sizes of the beam cross section and the void as well as the crystal orientation strongly influences both the elastic and the plastic behaviors of the beams. It was seen that the strain at plastic initiation increases with beam cross section size as well as with decreasing void size. It is further observed that the void deformed in different ways depending on cross section and void size. Sometimes void closure, leading to necking of the beam cross section followed by rupture occurred. In other cases the void elongated leading to that the two ligaments above and below the void ruptured independently.