Pseudoelasticity and shape memory effects in cylindrical FCC metal nanowires

Molecular dynamics simulations are used to show strong pseudoelasticity and shape memory effects in a wide range of face-centered cubic metal nanowires with cylindrical shape, while similar effects have only been previously reported in face-centered metal nanowires with a unique geometry, i.e., by crystal reorientation from 〈0 0 1〉/{1 0 0} with a square cross section to 〈1 1 0〉/{1 1 1} with a rhombic cross section. The more generalized pseudoelasticity and shape memory effects reported in this work are enabled via a simple yet experimentally practical approach by tilting the nanowire axis away from the perfect 〈0 0 1〉 or 〈1 1 0〉 orientation such that the symmetry is broken in those nanowires and only one slip system is activated during the uniaxial loading. It is shown that while no pseudoelasticity and shape memory effects are found in 〈1 1 0〉 or 〈0 0 1〉 oriented cylindrical nanowires, full recovery up to ∼50% tensile (or ∼ 30% compressive) strain can be achieved in cylindrical nanowires whose axis are tilted as small as 2° (or 4°) away from 〈1 1 0〉 (or 〈0 0 1〉). This finding could open up new opportunities for synthesizing shape-memory metal nanowires for vibration damping and mechanical energy storage applications at low cost.

510