Uniaxial tensile behavior of a bicrystal copper nanowire: Structural characterization with a Fourier transformation method

Molecular dynamics simulations have been used to investigate the uniaxial tensile behavior of the [1 1 0]‖[1 0 0] bicrystal copper nanowire. Due to the effect of grain boundary, the bicrystal nanowire breaks at the interface with strain increasing, showing a unique brittle feature. In order to well understand the crystallographic characters, we have developed a discrete Fourier transformation technique to analyze the periodic crystal structure. In particular, the atomic density distribution along the long axis of the nanowire is transformed into a frequency-amplitude relationship or into a normalized atomic density distribution. These two treatments enable us to further study the crystal grain orientation and the crystal structure in the stretching process. The frequency-amplitude analysis provides information about the large-scale crystallographic features while the local characteristics are mainly determined by the normalized atomic density distribution. From analyses of the simulation data, we have found that [1 1 0]‖[1 0 0] keeps good crystalline structure until breaking.