Ultratough nanocrystalline copper with a narrow grain size distribution

Abstract

We report a unique way of using mechanical milling/in situ consolidation at both liquid-nitrogen and room temperature to produce artifact-free nanocrystalline Cu(23nm) with a narrow grain size distribution. This nanocrystalline Cu exhibits an extraordinarily high yield strength (770MPa), as predicted from a Hall–Petch extrapolation, along with good ductility (comparable with ∼30% uniform tensile elongation). Possible factors leading to this excellent optimization of strength and ductility are discussed.