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

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.