Fundamental interaction process between pure edge dislocation and energetically stable grain boundary

The interaction between dislocations and grain boundaries is the principal factor for determining the mechanical properties and the plastic deformation behavior of metals. It is possible to control the grain-boundary microstructure and the macroscopic behavior has been widely exploited for scientific and industrial applications. In atomic scale, however, specific interaction characteristics such as the reaction energy and pathway have yet to be revealed. We have investigated the interaction process between a dislocation and an energetically stable grain boundary, and the quantitative characteristics were determined via atomistic transition state analysis. As a result, the interaction energy is found to be $1.16\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}1}\text{ }\text{eV}/\text{\AA{}}$, which is ${10}^{4}$ times higher than the Peierls potential. The lattice dislocations subsequently experience anomalous dissociations on the grain boundary, which becomes a key factor for the previously unexplained dislocation disappearance and grain-boundary migration.