Molecular-dynamics simulations of stacking-fault-induced dislocation annihilation in pre-strained ultrathin single-crystalline copper films

TL;DR

This study uses large-scale molecular-dynamics simulations to explore how stacking faults influence dislocation behavior and annihilation in pre-strained ultrathin copper films, revealing mechanisms of dislocation starvation independent of surface escape.

Contribution

It uncovers the role of stacking faults in dislocation dynamics and demonstrates dislocation starvation mechanisms in ultrathin copper films through molecular-dynamics simulations.

Findings

Stacking faults significantly affect dislocation dissociation and annihilation.

Dislocation starvation occurs in ultrathin films without dislocation escape.

Geometry plays a crucial role in the mechanical response of small-volume metallic structures.

Abstract

We report results of large-scale molecular-dynamics (MD) simulations of dynamic deformation under biaxial tensile strain of pre-strained single-crystalline nanometer-scale-thick face-centered cubic (fcc) copper films. Our results show that stacking faults, which are abundantly present in fcc metals, may play a significant role in the dissociation, cross-slip, and eventual annihilation of dislocations in small-volume structures of fcc metals. The underlying mechanisms are mediated by interactions within and between extended dislocations that lead to annihilation of Shockley partial dislocations or formation of perfect dislocations. Our findings demonstrate dislocation starvation in small-volume structures with ultra-thin film geometry, governed by a mechanism other than dislocation escape to free surfaces, and underline the significant role of geometry in determining the mechanical response of metallic small-volume structures.