Twin interaction with $\Sigma$11 tilt grain boundaries in BCC Fe : Formation of new grain boundaries

TL;DR

This study uses molecular dynamics simulations to explore how twins interact with $\\Sigma$11 tilt grain boundaries in BCC Fe, revealing the formation of new grain boundaries with specific dislocation structures during asymmetric tilt boundary interactions.

Contribution

It provides detailed atomistic insights into twin-GB interactions in BCC Fe, highlighting the formation of new grain boundaries in asymmetric tilt cases, which was not previously observed.

Findings

Twin nucleates from cracks or GBs.

New GBs form with $<$100$>$ Cottrell dislocations in asymmetric tilt cases.

No new GB formation observed in symmetric tilt interactions.

Abstract

It is well known that the twinning is an important mode of plastic deformation in nanocrystalline materials. As a result, it is expected that the twin can interact with different grain boundaries (GBs) during the plastic deformation. Understanding these twin-GB interactions is crucial for our understanding of mechanical behavior of materials. In this work, the twin interaction with different $\Sigma$11 symmetric and asymmetric tilt GBs has been investigated in BCC Fe using molecular dynamics (MD) simulations. The results indicate that twin nucleate from the crack or GB and, its interaction with $\Sigma$11 asymmetric tilt GBs leads to the formation of a new GB. This new GB consist of $<$100$>$ Cottrell type immobile dislocations. The detailed atomistic mechanisms responsible for this new GB formation have been revealed using atomistic simulations. Interestingly, the new GB formation has not been observed in the case of twin interaction with $\Sigma$11 symmetric tilt GBs.