Pseudoelastic behavior of Cu-Ni composite nanowires

We investigate the pseudoelastic behavior at room temperature of composite nanowires using molecular dynamics simulations. The nanowires are composed of a nickel core surrounded by a copper shell, leading to high coherency stresses. The coherency and surface stresses cause the nanowires to undergo a lattice reorientation, by twinning, from ⟨ 001 ⟩ to ⟨ 110 ⟩ during relaxation. Nanowires of different cross-sectional areas (varying from 2.17 × 2.17 up to 2.9 × 2.9 nm 2 ) were studied. In all cases, under tensile loading, the nanowires reorient to ⟨ 001 ⟩ and then under unloading reorient back to ⟨ 110 ⟩ , thus exhibiting pseudoelastic behavior. This behavior is more pronounced in composite nanowires with a coherent interface than for single crystal nanowires.