The effect of loading path on the mechanical behaviour of single crystalline copper nanowires was investigated with molecular dynamics simulations. Different loading conditions including pre-tensile torsion and pre-torsional tension at different temperatures were taken into consideration. It was found that elastic pre-loading conditions could induce a distinct weakening on the resistance against plastic deformation under later applied loads. Meanwhile, coupled thermal and pre-loading effect could also facilitate the transformation from elasticity to plasticity. Formations of fivefold twins were observed in copper nanowires subjected to the loading path with tension after pre-torsion. These fivefold twins all form at the necking stage before fracture, and were found to be pre-torsion- and size-dependent but insensitive to the change in temperature and cross-sectional shape. The results reported here indicate that the loading path effect on the mechanical behaviour plays an important role in the formation of some special microstructures such as multiple twins in metallic nanowires.

Loading Path Effect on the Mechanical Behaviour and Fivefold Twinning of Copper Nanowires. S.Jiang, H.Zhang, Y.Zheng, Z.Chen: Journal of Physics D, 2010, 43[33], 335402