Impact of diameter-to-length ratio on mechanical fatigue and cyclic behavior of gold nanowires: a molecular dynamics study

Gold nanowires (AuNWs) exhibit exceptional mechanical properties, making them promising for nanoscale electronics. However, their mechanical reliability under cyclic loading, particularly the effects of diameter-to-length ratio and pulling rate, remains insufficiently understood. This study addresses this knowledge gap by investigating the impact of these factors on the mechanical fatigue behavior of AuNWs using molecular dynamics simulations. Stress–strain analyses and common neighbor analysis (CNA) were employed to assess mechanical responses and structural evolution during cyclic deformation. The findings reveal that smaller AuNWs (e.g., 1 nm diameter) undergo rapid strain hardening due to limited dislocation nucleation, resulting in high stress capacity but brittle failure. In contrast, larger AuNWs (3–9 nm diameters) exhibit greater plastic accommodation and localized deformation, delaying failure and enhancing mechanical stability. The pulling rate further modulates these behaviors, with higher rates increasing peak stresses and lower rates promoting plastic relaxation. By elucidating the interplay between diameter, loading conditions, and fatigue behavior, this study provides novel insights into the structural reliability of AuNWs, offering a foundation for their optimized design in advanced nanoscale applications. Graphical abstract