Notch insensitive strength and ductility in gold nanowires

Abstract The initially defect-free nanowires were nanostructured with well-defined circular holes in the 19–62 nm regime by a He ion beam. The resulting flaw insensitivity and the effect of notches in single-crystalline  oriented Au nanowires on strength and ductility is demonstrated by in-situ tensile testing. Both, the atomistic simulation and transmission electron microscopy analysis, elucidated the mechanistic origin of the flaw-insensitivity, i.e. plastic flow initiation at the hole with the nucleation, propagation and interaction of Shockley partial dislocations, resulting in unique defect morphologies. The unique defect signature of post-mortem defects show in conjunction with accompanying large-scale atomistic simulation the build-up of an internal microstructure at the notch, which rationalizes the observed strain hardening and therefore allowed the unexpected extended ductility in notched nanowires.