Ideal strength of a Cu multi-shell nano-wire

Abstract The ideal strength of a nano-component, which is the maximum stress of the structure, provides an insight into minute material. We conducted tensile simulations for a cylindrical-shaped Cu nano-wire composed of an atomic chain as a core wrapped around by shell(s) with the structure of (111) layers in a fcc crystal. Young’s moduli and the ideal strengths of the wires are less than a single atomic chain and sheet. The mechanical strength of the wire is weakened by the following three factors: (a) changes in electron arrangement caused by combining core and shell; (b) a larger interatomic distance (inherent tensile strain) of the outer shell introduced for combining with the core chain; and (c) weak bonding (gap) on the outer shell caused by the mismatch of atomic layers due to the curvature difference. Factor (a) weakens the bonding of the shell(s) that occupy a greater part of the wire. A 5-1 wire, which consists of a core and a shell, is weakened compared with the single atomic chain and the single sheet due to (a) and (b). A 10-5-1 wire, consisting of a core and two shells, has less strength than a 5-1 wire due to (c) in addition to (a) and (b).