Abnormal grain growth in ultrafine grained Ni under high-cycle loading

Abnormal grain growth can occur in polycrystalline materials with only a fraction of grains growing drastically to consume other grains. Here we report abnormal ultrafine grained metal rarely explored high-cycle loading regime at ambient temperature. is observed electroplated Ni microbeams average initial sizes less than 640 nm under large number cycles (up 109) low strain amplitudes (< 0.3%). Such occurs predominantly the family whose <100> orientation along tensile/compressive direction. Micromechanics analysis suggests that elastic anisotropy dictates thermodynamic driving force growth, such lowest energy density oriented dominates growth. This work unveils unique type may be harnessed tailor microstructures materials.