Molecular Dynamics (MD) simulations have been carried to investigate the tensile deformation behavior of BCC Fe nanopillars with {100} and {110} twist grain boundaries (TWGBs) at 10 K. Mendelev's embedded atom method potential for BCC Fe has been chosen to describe the interatomic interaction. The TWGBs were obtained by rotating an upper and lower grains by an angle +2^° and -2^° around nanopillar axis in both <100> and <110> orientations. The simulation results indicate that the yielding in both the nanopillars is through dislocation emission. The deformation in nanopillar containing {100} TWGB was dominated by dislocation slip mechanism. In nanopillar having {100} TWGB, the deformation occurs by dislocation slip mechanism at low strains (up to ~ 11 %) followed by twinning at high strains. In general, the nanopillar containing {110} TWGB exhibited higher yield and flow stress than the nanopillar containing {100} TWGB.

Keywords: Molecular dynamics, Twist grain boundaries, BCC Fe nanopillars, Slip and twinning.