Study of grain boundary self-diffusion in iron with different atomistic models

Starikov, S. and Mrovec, M. and Drautz, R.

Volume: 188 Pages: 560-569
DOI: 10.1016/j.actamat.2020.02.027
Published: 2020

We studied grain boundary (GB) self-diffusion in body-centered cubic iron using ab initio calculations and molecular dynamics simulations with various interatomic potentials. A combination of different models allowed us to determine the principal characteristics of self-diffusion along different types of GBs. In particular, we found that atomic self-diffusion in symmetric tilt GBs is mostly driven by self-interstitial atoms. In contrast, in general GBs atoms diffuse predominantly via an exchange mechanism that does not involve a particular defect but is similar to diffusion in a liquid. Most observed mechanisms lead to a significant enhancement of self-diffusion along GBs as compared to diffusion in the bulk. The results of simulations are verified by comparison with available experimental data. © 2020 Acta Materialia Inc.

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