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- MakaleYalnız künye2027Scopus SJRQ2Design, structural characterization, and simulated radiation-transport assessment of high-entropy (GdErSmEuYb)2X2O7 (X = Hf, Zr, Ce, Si) rare-earth oxides
Güler, Ömer; Güler, Seval Hale; Yayla, Nihal; Baykal, Duygu Sen; Durmus, Hasan; Tekin, Huseyin Ozan; ALMisned, Ghada
This study investigates the structural, microstructural, surface-chemical, and radiation attenuation behaviour of high-entropy rare-earth oxide (HEO) powder compositions synthesized as TBC-related candidate coating materials, whose radiation attenuation potential was assessed within a computational Inconel-718-based sandwich model. Four compositions, namely (GdErSmEuYb)2Hf2O7, (GdErSmEuYb)2Ce2O7, (GdErSmEuYb)2Zr2O7, and (GdErSmEuYb)2Si2O7, were synthesized via high-energy ball milling followed by calcination at 1200 °C. X-ray diffraction results revealed the formation of distinct crystal structures depending on B-site chemistry, including defective fluorite and silicate-type phases. SEM-EDS mapping confirmed homogeneous elemental distribution, while XPS analysis demonstrated mixed valence states and different oxygen vacancy concentrations across the compositions. To evaluate radiation attenuation performance, a sandwich-type geometry consisting of a 10 mm Inconel-718 core with symmetrically defined simulated HEO layers was modelled using Monte Carlo simulations. Gamma-ray transmission was analyzed over an energy range of 0.276-1.332 MeV, and fast neutron attenuation was assessed at 4.5 MeV. The results showed that transmission factors decreased with increasing coating thickness, with the effect being more pronounced at lower photon energies. Among the investigated compositions, the Hf-based system exhibited the most favorable predicted attenuation response for both gamma rays and fast neutrons under the defined simulation conditions. Theoretical half-value layer calculations also showed good agreement with the simulation results. Overall, the findings indicate that high-entropy rare-earth oxide coatings may provide an additional radiation attenuation contribution when incorporated as layers in Inconel-718-based systems. However, since direct thermal-barrier properties such as thermal conductivity, thermal diffusivity, thermal cycling resistance, and thermal-stress behavior were not evaluated in the present work, the present study should be interpreted as a structural and radiation-transport assessment of TBC-related coating candidates rather than a direct demonstration of thermal-barrier performance.
- MakaleAçık Erişim2026Scopus SJRQ2Design and Characterization of Y2O3/Pr2O3–Enriched Inconel-718 Alloys for Nuclear Applications
Albayrak, Muhammet Gökhan; Güler, Ömer; Güler, Seval Hale; Evin, Ertan; ALMisned, Ghada; Sen Baykal, Duygu; Alkarrani, Hessa; Susoy, Gulfem; Kilic, Gokhan; Tekin, Hüseyin Ozan
This study explores the physical, structural, and radiation shielding enhancements in Inconel 718 superalloys reinforced with 1 wt% Y2O3 and varying Pr2O3 contents from 0 to 10 wt%, respectively. X-ray diffraction analysis confirmed preservation of the face-centered cubic structure, with increasing Pr2O3 inducing peak broadening and partial amorphization. The scanning electron microscopy/energy-dispersive X-ray spectroscopy results verified the homogeneous dispersion of oxides without agglomeration. Gamma-ray shielding parameters, including the mass attenuation coefficient (MAC), half-value layer, and effective atomic number, significantly improved with higher Pr2O3 content, particularly at low to mid photon energies. The 718Y-10PO sample exhibited the lowest transmission factors and the highest MAC values across all the tested energies. Buildup factors decreased in the Pr-rich samples, confirming reduced photon scattering. Notably, the fast neutron removal cross section for 718Y-10PO as 0.15521 cm−1 exceeded the benchmark materials like graphite and B4C. These findings establish the 718Y-10PO alloy as a promising candidate for advanced nuclear shielding applications, combining structural integrity with promising gamma and neutron attenuation capabilities.
