Co-development of significant elastic and reversible plastic deformation in nanowires

TL;DR

This study demonstrates that in GaAs nanowires, significant elastic and reversible plastic deformations can occur simultaneously under bending, challenging traditional views on deformation modes and showing partial recovery of plastic deformation.

Contribution

It provides experimental evidence and analysis of concurrent elastic and dislocation-based plastic deformation in nanowires, revealing reversible plasticity phenomena.

Findings

Plastic deformation recovers spontaneously upon stress release.

Simultaneous elastic and plastic deformation observed up to 6% strain.

Contrasts with traditional notions of deformation modes.

Abstract

When a material is subjected to an applied stress, the material will experience recoverable elastic deformation followed by permanent plastic deformation at the point when the applied stress exceeds the yield stress of the material. Microscopically, the onset of the plasticity usually indicates the activation of dislocation motion, which is considered to be the primary mechanism of plastic deformation. Once plastic deformation is initiated, further elastic deformation is negligible owing to the limited increase in the flow stress caused by work hardening. Here we present experimental evidence and quantitative analysis of simultaneous development of significant elastic deformation and dislocation-based plastic deformation in single crystal GaAs nanowires (NWs) under bending deformation up to a total strain of ~ 6%. The observation is in sharp contrast to the previous notions regarding the deformation modes. Most of the plastic deformation recovers spontaneously when the external stress is released, and therefore resembles an elastic deformation process.