A dual deformation mechanism of grain boundary at different stress stages

Abstract

Molecular dynamics (MD) simulation with embedded-atom method (EAM) potential was carried out to study the structure and shear response of an asymmetric tilt grain boundary in copper bicrystal. A non-planar structure with dissociated intrinsic stacking faults was observed in the grain boundary. Simulation results show that this type of structure can significantly increase the ductility of the simulation sample under shear deformation. A dual deformation mechanism of the grain boundary was observed; the grain boundary can be a source of dislocation emission and migrate itself at different stress stages. The result of this study can provide further information to understand the grain boundary mediated plasticity in nanocrystalline materials. Abstract: Molecular dynamics (MD) simulation with embedded-atom method (EAM) potential was carried out to study the structure and shear response of an asymmetric tilt grain boundary in copper bicrystal. A non-planar structure with dissociated intrinsic stacking faults was observed in the grain boundary. Simulation results show that this type of structure can significantly increase the ductility of the simulation sample under shear deformation. A dual deformation mechanism of the grain boundary was observed; the grain boundary can be a source of dislocation emission and migrate itself at different stress stages. The result of this study can provide further information to understand the grain boundary mediated plasticity in nanocrystalline materials.

Evaluation of Mechanical Properties of Σ5(210)/[001] Tilt Grain Boundary with Self-Interstitial Atoms by Molecular Dynamics Simulation

“…On the other hand, the subnanosecond timescale available to MD allows MD to address the evolution of the SIAs, but the motion of vacancies and their cluster is outside of the MD simulation time frame. Bicrystal models enable a well-controlled investigation of particular GB properties, and previous simulations took this advantage to study the mechanical properties of various GBs [38][39][40][41], and this approach was followed in the present study. The Cu Σ5(210)/[001] GB was taken as an example in this study; this is a typical high-angle boundary with a misorientation angle of 53.1 ∘ .…”