Molecular dynamic simulations were performed to investigate the effects of tensile and compressive loading on the mechanical properties of face-centered cubic single-crystal copper  nano-wires with diameters ranging from 2 to 10 nm. Characterization of the initial optimized structures revealed large variations in interatomic spacing, stress, and potential energy in all nano-wires, which resulted in tensile stress for surface atoms and compressive stress for internal atoms. This phenomenon is more apparent in thin nano-wires (<6 nm) than thick nano-wires (≥10 nm). These variations are the origins of asymmetric yielding and asymmetric Poisson ratio in  copper nano-wires during tension and compression. For example, the Poisson's ratio exceeds 0.5 as the compressive strain approaches yield, indicating that the mechanical properties of single-crystal  nano-wire show strong directionality. The finding provides a fundamental understanding of the influence of the wire diameter on the mechanical properties of  nano-wires.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)