Effect of surface energy on size-dependent deformation twinning of defect-free Au nanowires
Byungil Hwang, Mijeong Kang, Subin Lee, Christopher R. Weinberger, Phillip Loya, Jun Lou,e Sang Ho Oh, Bongsoo Kim and Seung Min Han
Nanoscale, 2015,7, 15657-15664
Received 13 Jun 2015, Accepted 17 Aug 2015
First published online 20 Aug 2015
In this study, we report the size-dependent transition of deformation twinning studied using in situ SEM/TEM tensile testing of defect-free  Au nanowires/ribbons with controlled geometry. The critical dimension below which the ordinary plasticity transits to deformation twinning is experimentally determined to be ∼170 nm for Au nanowires with equilateral cross-sections. Nanoribbons with a fixed thickness but increased width-to-thickness ratios (9 : 1) were also studied to show that an increase in the surface energy due to the crystal re-orientation suppresses the deformation twinning. Molecular dynamics simulations confirmed that the transition from partial dislocation mediated plasticity to perfect dislocation plasticity with increase in the width-to-thickness ratio is due to the effect of the surface energy.