Remarkable thermal stability of nanocrystalline CoCrFeNi high entropy alloy achieved through the incorporation of rare-earth element samarium

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dc.authorid0009-0001-6338-7076
dc.authorid0000-0001-9441-5175
dc.contributor.authorKotan, Hasan
dc.contributor.authorKoc, Recep C.
dc.contributor.authorBatibay, Ahmet B.
dc.date.accessioned2026-02-08T15:15:19Z
dc.date.available2026-02-08T15:15:19Z
dc.date.issued2025
dc.departmentBursa Teknik Üniversitesi
dc.description.abstractHigh entropy alloys (HEAs) with nanocrystalline grain sizes have received significant interest in recent years; however, their microstructural integrity is compromised by a tendency for grain growth due to their high-volume fraction of grain boundaries. Here, nanocrystalline CoCrFeNi with Sm addition was synthesized through mechanical alloying, followed by annealing at temperatures up to 1100 degrees C and for durations of up to 24 h. The results have revealed that the 16 +/- 6 nm as-milled grain size of CoCrFeNi experienced grain coarsening during the annealing process, reaching similar to 1.35 +/- 0.5 mu m and similar to 4.5 +/- 1.1 mu m after 1 and 24 h annealing at 1100 degrees C, respectively. This indicates that the nanocrystalline microstructure of CoCrFeNi lacks thermal stability at elevated temperatures. The average grain size was maintained at 110 nm after 1 h annealing at 1100 degrees C (T/T-m = 0.74) with Sm addition. Furthermore, while large grains (similar to 1.5 mu m) appeared after 24 h of annealing at 1100 degrees C, pockets of nano-sized grains were still present in the microstructure. The resistance to grain growth is ascribed to the presence of rare earth element, Sm, and the formation of Sm-based additional mixed oxide phases (Sm/Cr-O). Consequently, 517.8 +/- 25 HV as-milled hardness of CoCrFeNi decreased dramatically to 221.5 +/- 11 HV due to extensive grain growth but remained elevated at 442.5 +/- 15 HV (84 % of as-milled hardness) with Sm addition after annealing at 1100 degrees C. These findings highlight the potential for optimizing the thermal and mechanical performance of CoCrFeNi HEAs in various applications.
dc.description.sponsorshipScientific and Technological Research Council of Turkey (TUBITAK) [222M218]
dc.description.sponsorshipThis study was supported by Scientific and Technological Research Council of Turkey (TUBITAK) under the Grant Number 222M218. The authors thank to TUBITAK for their supports.
dc.identifier.doi10.1016/j.intermet.2024.108608
dc.identifier.issn0966-9795
dc.identifier.issn1879-0216
dc.identifier.scopus2-s2.0-85212575564
dc.identifier.scopusqualityQ1
dc.identifier.urihttps://doi.org/10.1016/j.intermet.2024.108608
dc.identifier.urihttps://hdl.handle.net/20.500.12885/5707
dc.identifier.volume178
dc.identifier.wosWOS:001394796900001
dc.identifier.wosqualityQ1
dc.indekslendigikaynakWeb of Science
dc.indekslendigikaynakScopus
dc.language.isoen
dc.publisherElsevier Sci Ltd
dc.relation.ispartofIntermetallics
dc.relation.publicationcategoryMakale - Uluslararası Hakemli Dergi - Kurum Öğretim Elemanı
dc.rightsinfo:eu-repo/semantics/closedAccess
dc.snmzWOS_KA_20260207
dc.subjectRare earth element
dc.subjectSamarium
dc.subjectHigh entropy alloys
dc.subjectGrain growth
dc.subjectThermal stability
dc.subjectIsothermal annealing
dc.subjectNanocrystalline
dc.titleRemarkable thermal stability of nanocrystalline CoCrFeNi high entropy alloy achieved through the incorporation of rare-earth element samarium
dc.typeArticle

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