Influence of twist boundary on deformation behaviour of <100> BCC Fe nanowires

TL;DR

This study uses molecular dynamics simulations to compare how twist boundaries affect deformation mechanisms in <100> BCC Fe nanowires, showing that boundaries influence whether slip or twinning dominates during deformation.

Contribution

It reveals the impact of twist boundaries on deformation modes in <100> BCC Fe nanowires, highlighting the shift from twinning to slip with boundary presence.

Findings

Perfect nanowires deform mainly by twinning and reorientation.

Nanowires with twist boundaries deform by slip at low strains, then twinning at high strains.

Dislocation slip is favored over twinning in the presence of initial dislocations.

Abstract

Molecular dynamics simulations revealed significant difference in deformation behaviour of $<$100$>$ BCC Fe nanowires with and without twist boundary. The plastic deformation in perfect $<$100$>$ BCC Fe nanowire was dominated by twinning and reorientation to $<$110$>$ followed by further deformation by slip mode. On the contrary, $<$100$>$ BCC Fe nanowire with a twist boundary deformed by slip at low plastic strains followed by twinning at high strains and absence of full reorientation. The results suggest that the deformation in $<$100$>$ BCC Fe nanowire by dislocation slip is preferred over twinning in the presence of initial dislocations or dislocation networks. The results also explain the absence of extensive twinning in bulk materials, which inherently contains large number of dislocations.