Fatigue behaviors and atomic-scale mechanisms in nanocrystalline gold thin film

The fatigue properties of 930 nm-thick Au films and 1 {\mu}m-thick Au film with a Ti interlayer are systematically investigated. The dominant damage behaviors of 930 nm-thick Au films under dynamic bending cyclic loading changed from extrusions to intergranular cracks with the decrease in strain ranges and the increase in cyclic cycles. The different fatigue behaviors are attributed to the process of edge dislocation annihilation and vacancy formation during cyclic deformation. Depositing 10 nm-thick Ti interlayers between the PI substrates and 1 {\mu}m-thick annealed Au films is effective to suppress strain localization and increase the rupture strain and the fatigue properties of thin Au films. This study shed lights on the fatigue mechanism and provide clues to design nanocomposites in the flexible displays in the practical application.