High-temperature radiation resistance of NiCoFe medium-entropy alloy enabled by stable nanostructures and defect evolution mechanisms

The study innovatively examined a nano oxide dispersion-strengthened (ODS) NiCoFe medium-entropy alloy with nanosized grains to address the challenge of discovering structural materials for high-temperature irradiation applications, such as in advanced nuclear reactors. The ODS-NiCoFe alloy exhibite...

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Veröffentlicht in:	Journal of materials research and technology Jg. 37; S. 5448 - 5464
Hauptverfasser:	Nori, Sri Tapaswi, Esfandiarpour, Amin, Kalita, Damian, Zieliński, Maciej, Mulewska, Katarzyna, Bjørge, Ruben, Vullum, Per Erik, Ferreirós, Pedro A., Chrominski, Witold, Li, Mingyang, Chang, Yongqin, Zhang, Yanwen, Diduszko, Ryszard, Macha, Nagini, Malladi, Sai Rama Krishna, Mason, Daniel R., Holmestad, Randi, Alava, Mikko, Kurpaska, Lukasz
Format:	Journal Article
Sprache:	Englisch
Veröffentlicht:	Elsevier B.V 01.07.2025 Elsevier
Schlagworte:	High-temperature irradiation Irradiation-hardening resistance Irradiation-swelling resistance Molecular dynamics damage cascade simulations Oxide dispersion-strengthened NiCoFe medium-entropy alloy Physical stability of nanostructures Oxide dispersion-strengthened NiCoFe medium-entropy alloy Physical stability of nanostructures Irradiation-swelling resistance Irradiation-hardening resistance Molecular dynamics damage cascade simulations High-temperature irradiation
ISSN:	2238-7854
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Zusammenfassung:	The study innovatively examined a nano oxide dispersion-strengthened (ODS) NiCoFe medium-entropy alloy with nanosized grains to address the challenge of discovering structural materials for high-temperature irradiation applications, such as in advanced nuclear reactors. The ODS-NiCoFe alloy exhibited a nanoindentation hardness of 4.3 ± 0.9 GPa, representing a two-fold enhancement over the 2.0 ± 0.1 GPa of single-crystal NiCoFe. Dislocations were identified as the primary defect structures. Following irradiation (Ni2+, 580 °C), the average dislocation length density increased from ∼2.6 × 1013 m−2 to ∼6.1 × 1013 m−2, while the mean dislocation length decreased from 249 nm to 104 nm, contributing to a relative irradiation hardening of 25 %. Additionally, the study demonstrated the stability of various nanostructures, with only minor changes in the average sizes of nanoprecipitates and grains—from 6.7 ± 1.7 nm to 6.4 ± 1.7 nm, and from 73 ± 2 nm to 76 ± 2 nm, respectively, upon irradiation, suggesting effective defect annihilation at interfaces and grain boundaries. The alloy exhibited no observable irradiation-induced voids. Molecular dynamics simulations revealed irradiation resistance of the alloy through the absorption of vacancy clusters at grain boundaries and Shockley-dominant-dislocation chains and the absorption of interstitial clusters at grain boundaries, aided by the high mobility and three-dimensional motion of interstitial clusters. Thus, the findings demonstrate the high-temperature radiation resistance of the novel ODS-NiCoFe alloy, surpassing that of well-known ODS steels, using a correlative approach that combines experiments and simulations.
ISSN:	2238-7854
DOI:	10.1016/j.jmrt.2025.07.079