Barrios, AlejandroZhang, YinMaeder, XavierCastelluccio, Gustavo M.Pierron, OlivierZhu, Ting2021-12-072021-12-072021-11-02Barrios A, Zhang Y, Maeder X, et al., (2022) Abnormal grain growth in ultrafine grained Ni under high-cycle loading, Scripta Materialia, Volume 209, March 2022, Article number 1143721359-6462https://doi.org/10.1016/j.scriptamat.2021.114372https://dspace.lib.cranfield.ac.uk/handle/1826/17314Abnormal grain growth can occur in polycrystalline materials with only a fraction of grains growing drastically to consume other grains. Here we report abnormal grain growth in ultrafine grained metal in a rarely explored high-cycle loading regime at ambient temperature. Abnormal grain growth is observed in electroplated Ni microbeams with average initial grain sizes less than 640 nm under a large number of loading cycles (up to 109) with low strain amplitudes (< 0.3%). Such abnormal grain growth occurs predominantly in the family of grains whose <100> orientation is along the tensile/compressive loading direction. Micromechanics analysis suggests that the elastic anisotropy of grains dictates the thermodynamic driving force of abnormal grain growth, such that the lowest strain energy density of the <100> oriented grain family dominates grain growth. This work unveils a unique type of abnormal grain growth that may be harnessed to tailor grain microstructures in materials.enAttribution-NonCommercial-NoDerivatives 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-nd/4.0/Abnormal grain growthHigh-cycle loadingMicromechanicsUltrafine grained metalArticle