[P2-14] Atomistic insights into the grain boundaries interaction with radiation-induced point defects in bcc Fe-Cr alloys
Grain boundaries (GBs) are an immanent components of crystal structure of the structural materials, such as e.g. Fe-Cr steels. Moreover, they have considerable influence on the materials properties, especially on the mechanical one. As a consequence of that, is necessary to investigate effect of radiation-induced defects on the GBs in order to a deeper understanding of the radiation damage.
In current study, we investigated characteristics of bcc-Fe and Fe-Cr based tilt GBs interacting with point defects such as vacancy, self-interstitial (SIA, dumbbell-type), and interstitial atoms (He impurities). Several tilt GBs with the rotation axis along [100] and [110] directions were modelled with He impurities, vacancy, and SIA in Fe-Cr. Molecular dynamics (MD) simulations using the interatomic Fe-Cr-He embedded atom model potential were conducted, for twelve GBs, in order to investigate GBs energies, He segregation energies, and the weakening effect of He impurity for several Cr and He concentrations. Furthermore, spin-polarized density functional theory (DFT) calculations focused at two GBs, Σ3(111) and Σ5(210), allowed to deeper insights into GBs properties. For example, the DFT results show that the presence of He significantly influences the magnetic properties of the system in the relatively distant neighbourhood [1]. The fluctuation of magnetic moments, chemical potentials, formation and migration energies of point defects were studied as a function of distance from GB’s plane. Representative structures of GBs, with Cr content ranging 6-10%, generated using DFT-based Monte Carlo simulations [2] were used to analyse how parameters, such as alloy short-range ordering or local environment, effects on defects properties.
[1]. M. R. Zemla, J. S. Wrobel, T. Wejrzanowski, D. Nguyen-Manh, K. J. Kurzydlowski, Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms 393:118 (2017).
[2]. J.S. Wrobel, D. Nguyen-Manh, M.Y. Lavrentiev, M. Muzyk, S.L. Dudarev, Physical Review B 91 (024108) 2015.
In current study, we investigated characteristics of bcc-Fe and Fe-Cr based tilt GBs interacting with point defects such as vacancy, self-interstitial (SIA, dumbbell-type), and interstitial atoms (He impurities). Several tilt GBs with the rotation axis along [100] and [110] directions were modelled with He impurities, vacancy, and SIA in Fe-Cr. Molecular dynamics (MD) simulations using the interatomic Fe-Cr-He embedded atom model potential were conducted, for twelve GBs, in order to investigate GBs energies, He segregation energies, and the weakening effect of He impurity for several Cr and He concentrations. Furthermore, spin-polarized density functional theory (DFT) calculations focused at two GBs, Σ3(111) and Σ5(210), allowed to deeper insights into GBs properties. For example, the DFT results show that the presence of He significantly influences the magnetic properties of the system in the relatively distant neighbourhood [1]. The fluctuation of magnetic moments, chemical potentials, formation and migration energies of point defects were studied as a function of distance from GB’s plane. Representative structures of GBs, with Cr content ranging 6-10%, generated using DFT-based Monte Carlo simulations [2] were used to analyse how parameters, such as alloy short-range ordering or local environment, effects on defects properties.
[1]. M. R. Zemla, J. S. Wrobel, T. Wejrzanowski, D. Nguyen-Manh, K. J. Kurzydlowski, Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms 393:118 (2017).
[2]. J.S. Wrobel, D. Nguyen-Manh, M.Y. Lavrentiev, M. Muzyk, S.L. Dudarev, Physical Review B 91 (024108) 2015.