Nanotwinned(NT)metal represents a unique hierarchical nanostructured material,with a large number of highly organized nanoscale twins embedded within micro-or submicro-sized grains.Twin boundaries(TBs)are effective barriers blocking dislocation motion and thus substantially strengthen metals,as effectively as general high-angle grain Nanotwinned (NT) metal represents a unique hierarchical nanostructured material, with a large number of highly organized nanoscale twins embedded within micro-or submicro-sized grains. TW boundaries (TBs) are effective barriers blocking dislocation motion and therefore able strong metals, as effectively as general high-angle grain