Shear response of 〈110〉 asymmetric tilt grain boundaries in BCC-Fe

Abstract

The present study investigated the effect of shear load on the <110> asymmetric tilt grain boundaries of body-centered cubic iron with molecular dynamics simulations. Various mechanisms like grain boundary (GB) sliding, shear-coupled migration, GB migration with rotation, GB decomposition, and GB deformation with dislocations emission were observed. Low-angle tilt GBs migrated with the help of two dislocation mechanisms, gliding and climbing. Two types of twin nucleation mechanisms were noticed in high-angle tilt GBs with varying tilt angles (η). For 16 ̊ ≤ η ≤ 112 ̊ and η ≥ 130 ̊ cases, dynamic self-adjustment of the atoms at the GBs caused GBs decomposition with the formation of twin boundaries (TBs). Newly nucleated TBs migrated under further applied shear load. For 112 ̊ < η < 130 ̊ case, TBs nucleated from the GB on either side of the misfit dislocations due to their localized core structure on the GB plane.