Approaching the theoretical elastic strain limit in copper nanowires

Three sets of uniaxial tensile tests have been performed in situ in transmission electron microscopy/high-resolution electron microscopy on Cu nanowires (NWs) to accurately map out the sample size dependence of elastic strain limit. Atomic-resolution evidence was obtained for an exceedingly large recoverable strain (as much as 7.2%) that can be sustained in the lattice of a single-crystalline Cu NW with a diameter of ∼5.8 nm. This ultrahigh elastic strain is consistent with the predictions from molecular dynamics simulations for nanowires and approaches the ideal elastic limit predicted for Cu by ab initio calculations.