Interstitial emission at grain boundary in nanolayered alpha-Fe

XZ Tang and YF Guo and Y Fan and S Yip and B Yildiz, ACTA MATERIALIA, 105, 147-154 (2016).

DOI: 10.1016/j.actamat.2015.12.009

The Autonomous Basin Climbing method and Rate Theory are applied to investigate the interstitial emission mechanism in alpha-Fe. The atomic trajectories and potential energy landscape of the interstitial emission process induced by the Sigma 3 < 110 >111 symmetrical tilt grain boundary are presented. By comparing with vacancy hopping mechanism, the grain boundary influence range at finite temperature is revealed. We uncover the energetic and geometric essentials of the interstitial emission mechanism, and find connections between two previously reported defect-grain boundary interactions at long time scale. Surprisingly in nanolayered structures, higher grain boundary density raises the activation energy barriers of interstitial emission. This phenomenon is strongly correlated with the energy and local stress distribution of the grain boundary. (C) 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

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