Microstructural evolution, nanoindentation creep response, and wear properties of Y2O3-modified CoCrFeNi high entropy alloys

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dc.contributor.authorTekin, Mustafa
dc.contributor.authorKotan, Hasan
dc.contributor.authorBalci, Erdem
dc.contributor.authorKaba, Mertcan
dc.contributor.authorBaydogan, Murat
dc.contributor.authorBayrak, Kubra Gurcan
dc.contributor.authorAyas, Erhan
dc.date.accessioned2026-02-08T15:15:22Z
dc.date.available2026-02-08T15:15:22Z
dc.date.issued2026
dc.departmentBursa Teknik Üniversitesi
dc.description.abstractThe combined effects of wear and creep largely determine the long-term reliability of alloys in demanding thermal and mechanical environments, but conventional structural materials show limited resistance to these degradation mechanisms. High-entropy alloys (HEAs), though inherently robust, have gained attention as potential candidates for such environments, particularly when reinforced with stable oxide dispersions. In this study, oxide-dispersion-strengthened Co-Cr-Fe-Ni HEAs containing 1 and 4 wt% Y2O3 were synthesized through mechanical alloying and spark plasma sintering to evaluate this approach. Microstructural characterization using X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirmed the retention of the fcc crystal lattice. Pronounced grain refinement was achieved, decreasing from 360 +/- 70 nm in the unreinforced HEA to 95 +/- 15 nm in the 4 wt% ODS composition, accompanied by a substantial increase in hardness to 685 +/- 30 HV. Wear experiments revealed a fourfold reduction in specific wear rate. This improvement was accompanied by a transition in wear mode from extensive surface damage in the unreinforced HEA to predominantly oxidative and fatigue-assisted mechanisms in the ODS HEAs, facilitated by the formation of protective tribo-oxide layers. Nanoindentation creep analysis revealed a decrease in stress exponent from 16.05 to 5.72 with increasing Y2O3 content. This change signifies a transition toward dislocation-controlled creep and tunable creep resistance. Collectively, these findings establish that rare-earth oxide dispersion is an effective strategy for simultaneously enhancing surface durability and controlling time-dependent deformation in HEAs, thereby extending their potential for demanding structural and tribological applications.
dc.identifier.doi10.1016/j.matchar.2025.115942
dc.identifier.issn1044-5803
dc.identifier.issn1873-4189
dc.identifier.scopus2-s2.0-105027389025
dc.identifier.scopusqualityQ1
dc.identifier.urihttps://doi.org/10.1016/j.matchar.2025.115942
dc.identifier.urihttps://hdl.handle.net/20.500.12885/5745
dc.identifier.volume231
dc.identifier.wosWOS:001658023600001
dc.identifier.wosqualityQ1
dc.indekslendigikaynakWeb of Science
dc.indekslendigikaynakScopus
dc.language.isoen
dc.publisherElsevier Science Inc
dc.relation.ispartofMaterials Characterization
dc.relation.publicationcategoryMakale - Uluslararası Hakemli Dergi - Kurum Öğretim Elemanı
dc.rightsinfo:eu-repo/semantics/closedAccess
dc.snmzWOS_KA_20260207
dc.subjectHigh entropy alloys
dc.subjectOxide dispersion strengthening
dc.subjectSpark plasma sintering
dc.subjectWear properties
dc.subjectNanoindentation creep
dc.subjectCreep mechanism
dc.titleMicrostructural evolution, nanoindentation creep response, and wear properties of Y2O3-modified CoCrFeNi high entropy alloys
dc.typeArticle

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