Y-Ti-O Nanocluster Formation in Bcc Fe Using Dft and Kinetic Monte Carlo Simulations


Y-Ti-O Nanocluster Formation in Bcc Fe Using Dft and Kinetic Monte Carlo Simulations

Murali, D.; Kaur, G.; Jegadeesan, P.; Panigrahi, B. K.; Valsakumar, M. C.; Posselt, M.

Oxide Dispersion Strengthened (ODS) steels are candidate materials for use in nuclear environment as they offer excellent swelling resistance characteristics and enhanced high temperature mechanical properties. ODS steels derive their strength from the dispersion of oxide (Y-Ti-O) nanoclusters in the ferritic matrix. The mechanism of formation, structure, thermal & radiation stability and composition of these nanoclusters are not yet fully understood. We are studying the basic energetic and kinetic properties of solutes and their clusters along with vacancy in bcc Fe using density functional theory and evolution of these nanoclusters using kinetic Monte Carlo simulations. The diffusion coefficients of these solute atoms in bcc Fe have been calculated using Le Claire's nine frequency model. Among these, Y is believed to be rate limiting for the growth of nanoclusters and our calculated diffusion coefficient is found to be three orders of magnitude higher than the experimental one [J. Nucl. Mater. 419, 208 (2011)]. In order to further understand the diffusion behavior of Y in bcc Fe and hence its role in the kinetics of nanocluster formation, we review the Le Claire's diffusion model both in dilute and concentrated limits. Also, in continuation of our previous study of solute atom interaction with vacancy, we discuss our recent results of DFT calculations of solute atom interactions with self-interstitials.

Keywords: ODS; DFT; KMC

  • Lecture (Conference)
    Multiscale Materials Modeling (MMM) 2012, 15.-19.10.2012, Singapore, Singapore

Permalink: https://www.hzdr.de/publications/Publ-17940
Publ.-Id: 17940