Mechanical Properties Of Helical Metallic Nano Springs

Helical metallic nanosprings (HMNSs) with a range of shape and size parameters were studied via atomistic simulations. The springs are found outstandingly elastic upon tension, with measured stiffness following very well the scaling rules developed for micro- and macro-sized coiled springs. As the stored elastic energy reaches maximum, they become unsuitable to carry steady load due to dislocation nucleation events at surfaces. The onset of plasticity is dominated by dislocation slip as well as deformation twinning. Dislocations may lock each other and Eshelby twists may be generated as a direct consequence of shear and torsion forces built-in with the helical geometry. Our results suggest that metallic nanosprings are quite applicable nanoscale devices with desirable elasticity and controllable strength or stiffness.