Keywords nano-crystalline materials;face-centered-cubic metals;twin;grain boundary sliding;grain rotation;ductile-to-brittle transition;bimodal grain size materials;ductility;

• 关键词纳米材料;面心立方金属;孪晶;晶界滑移;晶粒转动;韧-脆转变;双峰晶粒材料;塑性;