Influence of foreign atoms on the diffusion of oxygen in bcc Fe

In this research project (started in September 2016) the diffusion of foreign atoms in bcc Fe shall be investigated by first-principle methods and kinetic Monte Carlo simulations. The focus of the present work is on the diffusion of oxygen under the influence of other foreign atoms such as Al, Cr, Si, Ti, and Y. Oxygen plays e.g. an important role in the formation and evolution of nanoclusters in nanostructured ferritic Fe-Cr alloys which are considered as promising candidates for structural materials of future fusion and fission reactors [1]. In bcc Fe the most stable site of oxygen is the octahedral interstitial position and the tetrahedral interstitial position is the saddle point for the migration [2-5]. The presence of foreign atoms and intrinsic point defects modifies the migration path [5-7]. Using DFT calculations the binding energy between oxygen and a foreign atom is determined for different neighbor distances. Then the modified migration barriers are calculated, i.e. for the O jump between the first and the second neighbor of a foreign atom, etc. The results shall be used in kinetic Monte Carlo simulations of the whole diffusion process and for the determination of the corresponding diffusion coefficient in dependence on the concentration of foreign atoms. Finally, the calculated diffusion coefficient shall be compared with the few existing experimental data on oxygen diffusion in dilute iron alloys.
[1] G. R. Odette, JOM-J. Min. Met. Mat. S. 66, 2427 (2014)
[2] C.L. Fu, M. Krcmar, G.S. Painter, X.-Q. Chen, Phys. Rev. Lett. 99, 225502 (2007)
[3] D. Murali, B.K. Panigrahi, M.C. Valsakumar, S. Chandra, C.S. Sundar, B. Raj, J. Nucl. Mater. 403, 113 (2010)
[4] A. Claisse, P. Olsson, Nucl. Instr. Meth. B 303, 18 (2013)
[5] S.L. Shang, H.Z. Fang, J. Wang, C.P. Guo, Y. Wang, P.D. Jablonski, Y. Du, Z.K. Liu, Corrosion Sci. 83, 94 (2014)
[6] P. Liu, W. Xing, X. Cheng, D. Li, Y. Li, X.-Q. Chen, Phys. Rev. B 90, 024103 (2014)
[7] C. Barouh, T. Schuler, C.-C. Fu, T. Jourdan, Phys. Rev. B 92, 104102 (2015)