Fedorov, Mark; Wróbel, Jan S.; London, Andrew J.; Kurzydłowski, Krzysztof J.; Fu, Chu-Chun; Tadić, Tonči; Dudarev, Sergei L.; Nguyen-Manh, Duc (2023) Precipitation of Cr-rich clusters in Fe-Cr alloys: Effects of irradiation from first principles modeling and experimental observations. Journal of Nuclear Materials, 587 . ISSN 0022-3115
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Abstract
Using exchange Monte Carlo (MC) simulations based on an ab initio-parameterized Cluster Expansion (CE) model, we explore the phase stability of low-Cr Fe-Cr alloys as a function of vacancy (Vac), carbon, and nitrogen content. To parameterize the CE model, we perform Density Functional Theory calculations for more than 1600 supercells containing Cr-Vac-C-N clusters of various sizes in pure bcc Fe, Cr, and Fe-Cr alloys. MC simulations performed for T = 650 K show that Cr clustering in Fe-3.28 at.%Cr alloys does not occur if there are no defects or if only vacancies are present. But the addition of a small amount of C or N, at the level as low as 0.02 at.% in an alloy with no vacancies, routinely results in the formation of ordered compounds containing a high amount of Cr, C and N. Cr segregates to interstitial atoms and Cr content in such Cr-rich clusters increases as a function of C and/or N concentration. In the presence of vacancies, C/N aggregate to the core regions of vacancy clusters, making segregation of Cr-rich clusters less pronounced. The structure of Cr-rich clusters varies significantly, depending on the concentration of interstitial atoms and on the ratio of N to C. Predictions derived from MC simulations agree with experimental observations of Fe-Cr alloys exposed to ion irradiation. The concentration of Cr found in clusters containing C and N interstitial atoms is in qualitative agreement, and the absolute Cr content found in the clusters simulated at 650 K is in quantitative agreement with experimental Atom Probe Tomography (APT) observations of Fe-3.28 at.%Cr alloys irradiated at 623 K. The measured C and N content of 42±5 and 151±3 atomic ppm likely results from the contamination that occurred during ion beam irradiation.
| Item Type: | Article | ||||||||
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| Uncontrolled Keywords: | irradiation effects; Fe Cr alloys; density functional theory (DFT); cluster expansion (CE); Monte Carlo simulations; atom probe tomography (APT) | ||||||||
| Subjects: | NATURAL SCIENCES > Physics | ||||||||
| Divisions: | Division of Experimental Physics | ||||||||
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| Depositing User: | Ivana Vuglec | ||||||||
| Date Deposited: | 15 Apr 2026 12:58 | ||||||||
| URI: | http://fulir.irb.hr/id/eprint/11720 | ||||||||
| DOI: | 10.1016/j.jnucmat.2023.154715 |
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