Hybrid effect of Sm and B4C on grain size stability and hardness of nanocrystalline CoCrFeNi high entropy alloy after isothermal annealing

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dc.authorid0009-0001-6338-7076
dc.contributor.authorTasdemir, Esma
dc.contributor.authorKoc, Recep C.
dc.contributor.authorBatibay, Ahmet B.
dc.contributor.authorKotan, Hasan
dc.date.accessioned2026-02-08T15:15:19Z
dc.date.available2026-02-08T15:15:19Z
dc.date.issued2025
dc.departmentBursa Teknik Üniversitesi
dc.description.abstractIn this study, a hybrid effect of Sm and B4C additions is explored to enhance the thermal stability of mechanically alloyed nanocrystalline CoCrFeNi HEA after exposures to long-term annealing at 700 degrees C and 900 degrees C. The structural and microstructural investigations were carried out using X-ray diffraction (XRD), focused ion beam microscopy (FIB), and scanning transmission electron microscopy (STEM) with energy dispersive spectroscopy (EDS). The results revealed that 7 nm grain size of as-milled CoCrFeNi HEA coarsened to 247.38 f 69 nm after 1 h of annealing at 900 degrees C. However, the hybrid addition of Sm and B4C significantly retarded grain growth, reducing the average grain size to 98.74 f 47 nm after 24 h of annealing at the same temperature. The resistance to grain growth is attributed to Sm and B4C additions and the formation of Sm-based oxide phases during annealing. The influence of microstructures on hardness was utilized to examine the mechanical changes as a function of annealing temperature and annealing time. Accordingly, the hardness of CoCrFeNi, measured as 517.8 f 25 HV after mechanical alloying, decreased significantly to 321 f 10 HV and 277 f 13 HV after 1 and 24 h of annealing at 900 degrees C, respectively. In contrast, the hybrid HEA maintained a hardness of 439.5 f 10 HV even after 24 h of annealing at 900 degrees C. Compared to the individual additions of Sm and B4C, the hybrid addition also proved more effective in preserving hardness at elevated temperatures over time. Overall, exploring the hybrid effect of alloying and second-phase addition provides a promising strategy for improving the grain size stability and the mechanical properties of nanocrystalline CoCrFeNi HEAs.
dc.description.sponsorshipScientific and Technological Research Council of Turkiye (TUBITAK) [222M218]; TUBITAK
dc.description.sponsorshipThis study was supported by the Scientific and Technological Research Council of Turkiye (TUBITAK) under Grant Number 222M218. The authors thank TUBITAK for their support.
dc.identifier.doi10.1016/j.jallcom.2025.179807
dc.identifier.issn0925-8388
dc.identifier.issn1873-4669
dc.identifier.scopus2-s2.0-105000189446
dc.identifier.scopusqualityQ1
dc.identifier.urihttps://doi.org/10.1016/j.jallcom.2025.179807
dc.identifier.urihttps://hdl.handle.net/20.500.12885/5716
dc.identifier.volume1022
dc.identifier.wosWOS:001468217400001
dc.identifier.wosqualityQ1
dc.indekslendigikaynakWeb of Science
dc.indekslendigikaynakScopus
dc.language.isoen
dc.publisherElsevier Science Sa
dc.relation.ispartofJournal of Alloys and Compounds
dc.relation.publicationcategoryMakale - Uluslararası Hakemli Dergi - Kurum Öğretim Elemanı
dc.rightsinfo:eu-repo/semantics/closedAccess
dc.snmzWOS_KA_20260207
dc.subjectHigh entropy alloys
dc.subjectNanocrystalline
dc.subjectGrain growth
dc.subjectHybrid effect
dc.subjectThermal stability
dc.subjectIsothermal annealing
dc.subjectSm
dc.titleHybrid effect of Sm and B4C on grain size stability and hardness of nanocrystalline CoCrFeNi high entropy alloy after isothermal annealing
dc.typeArticle

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