Molecular dynamics simulation of effects of microstructure and loading mode on mechanical properties of Au nanowires

The effects of microstructure and loading mode on the mechanical properties of Au nanowires (NWs) are studied using molecular dynamics simulations based on the many-body embedded-atom potential. The effects are investigated in terms of common neighbour analysis, shear strain distribution, and stress-strain curves. The microstructure effect is examined using single-crystalline (SC), nanocrystalline (NC), and amorphous (AC) structures. The simulation results show that during tension, SC, NC, and AC NWs have visually similar deformations and similar ultimate strains, but completely different deformation mechanisms. For all loading modes, the SC NWs have the highest tensile and shear strength values and the NC NWs have the highest compressive strength. The AC NWs have poor strength under tensile, compressive, and shear loadings. The presence of grain boundaries increases the geometric instability of the NC NWs under compression and shear loadings.