Effect of Surface Crack and its Size on Mechanical Characteristics of Gold Nano-wires

Nano-crystalline materials are well known for properties resulting from well ordered structure and lack of unevenness due to presence of defects like cracks, inclusions, voids etc. Occurrence of these defects in nano-crystalline materials cannot be ignored and their presence strongly influences many of the properties of the materials. In present study, atomistic simulations have been used to investigate the torsional mechanical properties of gold nano-wires having surface-crack like defect. Cracks with its length parallel to nano-wire axis and its width lying in radial direction, carrying various depths have been created on the nano-wire surface. Crack is positioned at center of nano-wire in longitudinal direction. On the cross-section of the nano-wire, loading is applied at a particular twisting rate. The inter-atomic interactions are represented by employing Embedded Atom Potential (EAM). The effect of different sizes of the crack on strain energy due to twisting, torsional stiffness (or torsional rigidity) of the nano-wire has been investigated. It is predicted from our simulations that there is significant effect of the surface crack and its size on the mechanical properties of the gold nano-wire.