About this Abstract |
Meeting |
2022 TMS Annual Meeting & Exhibition
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Symposium
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Materials Systems for the Future of Fusion Energy
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Presentation Title |
Anomalous Precipitation of Cr in Fe-rich Ferritic Steels under Irradiation in Presence of C and N Impurities: First Principles Modeling and Experimental Observations |
Author(s) |
Mark Fedorov, Jan Wróbel, Andrew London, Krzysztof Kurzydłowski, Sergei Dudarev, Duc Nguyen-Manh |
On-Site Speaker (Planned) |
Mark Fedorov |
Abstract Scope |
Cluster Expansion (CE) model based on Density Functional Theory (DFT) calculations was developed for Fe-Cr alloys with interstitial C and N, representing steels impurities, and vacancies, representing radiation defects. The model is constructed from two sublattices: (i) Fe-Cr matrix with vacancies on bcc sublattice and (ii) the interstitial defects on octahedral sublattice.
Binding energies obtained in DFT calculations reproduce the results from previous studies for Fe-C(N) systems. The cross-validation error between DFT and CE model is 5 meV.
MC simulations for Fe-rich alloys show that interstitial defects are strongly attracted to each other and to vacancies, forming gas bubbles/graphite precipitations and/or alpha-cementite-like precipitations with Cr concentration increased as compared to the nominal Cr concentration.
Our modeling results at 650K are in agreement with the recent APT experimental observations of the anomalous precipitation of Cr in Fe-5.8% Cr ferritic steels under irradiation, which is spatially correlated with the C/N defect clusters. |
Proceedings Inclusion? |
Planned: |
Keywords |
Modeling and Simulation, Iron and Steel, Nuclear Materials |