Yazarlar

• Güler, Ömer(6)
• ALMisned, Ghada(5)
• Güler, Seval Hale(4)
• Tekin, H.O.(3)
• Alkarrani, Hessa(2)
• Baykal, Duygu Sen(2)
• Durmus, Hasan(2)
• Sen Baykal, Duygu(2)
• Susoy, Gulfem(2)
• Tekin, Huseyin Ozan(2)
• ALmisned, Ghada(1)
• Akkurt, Iskender(1)
• Albayrak, M. Gokhan(1)
• Albayrak, Muhammet Gökhan(1)
• Birdogan, Selcuk(1)
• Evin, Ertan(1)
• Günoglu, Kadir(1)
• Ilik, E.(1)
• Issa, Bashar(1)
• Kavaz, E.(1)
• Kilic, G.(1)
• Kilic, Gokhan(1)
• Ozkavak, Hatice Varol(1)
• Tekin, Hüseyin Ozan(1)
• Yayla, Nihal(1)
• Özkul, İskender(1)

• MakaleYalnız künye2027Scopus SJRQ2/r/munzur/1135
  Design, 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.

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• MakaleAçık Erişim2026Scopus SJRQ2/r/munzur/1433
  Design 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.

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• MakaleYalnız künye2026Scopus SJRQ2/r/munzur/1432
  Synthesis, structural characterization, and radiation interaction behaviour of (ErSmGdYPr)2Hf2O7 high-entropy oxide powder: A preliminary investigation for potential applications in nuclear environments

  Güler, Ömer; Güler, Seval Hale; Özkul, İskender; ALMisned, Ghada; Baykal, Duygu Sen; Tekin, Huseyin Ozan

  This study represents an initial investigation toward exploring the multifunctional potential of the (ErSmGdYPr)2Hf2O7 high-entropy oxide as a thermal barrier coating (TBC) material in radiation environments. Therefore, the evaluated parameters should be considered as a preliminary step rather than a complete representation of the material’s overall performance in such complex applications. In this context, (ErSmGdYPr)₂Hf2O7 powders were synthesized through high-energy ball milling of commercial rare-earth oxide precursors followed by calcination at different temperatures. Structural evolution during synthesis was investigated using X-ray diffraction, scanning electron microscopy with energy-dispersive spectroscopy, and thermal analysis techniques. The results confirmed the formation of a defective fluorite-type high-entropy oxide structure after calcination at elevated temperatures, accompanied by homogeneous elemental distribution and stable ceramic microstructures. In addition to structural characterization, the radiation interaction behaviour of the synthesized material was evaluated through gamma-ray attenuation parameters and fast neutron removal cross-section analysis. The obtained results indicate that the presence of multiple rare-earth elements provides favorable interaction characteristics with both photons and fast neutrons. These findings highlight the potential of this high-entropy oxide as a precursor for multifunctional coating materials. However, it should be noted that this work represents a preliminary powder-level investigation, and further research on actual coating deposition and thermal testing is required to validate its service performance.

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• MakaleYalnız künye2026Scopus SJRQ2/r/munzur/1244
  Structural evolution and radiation shielding performance of nano-HfO2 doped lithium borotellurite glasses

  Durmus, Hasan; Kilic, G.; Ilik, E.; Kavaz, E.; Güler, Ömer; Birdogan, Selcuk; ALMisned, Ghada; Tekin, H.O.

  This study investigates the structural evolution and radiation shielding performance of lithium borotellurite glasses reinforced with nano-sized HfO2. We report on the competitive dynamics between the depolymerizing nature of the Li + network modifier and the high field strength Hf4+ nano-dopant, a relationship not previously explored in this matrix. Structural analysis via XRD and TEM reveals that the glass remains fully amorphous with homogeneously dispersed Hf rich nanodomains up to 4 mol%. A critical solubility threshold is identified at 6 mol%, where the precipitation of HfO2 and HfTe3O8 crystalline phases marks a distinct transition from an amorphous state to a glass-ceramic microstructure. Physical property measurements indicate that Hf4+ ions primarily occupy interstitial free volumes, leading to enhanced material density without significant network dilation. The incorporation of nano-HfO2 significantly augments gamma-ray attenuation efficiency, particularly in the low-energy region, by substantially increasing the effective atomic number and reducing the half value layer. Furthermore, the glasses exhibit robust fast-neutron shielding capabilities, outperforming conventional materials such as graphite and B4C. These findings establish nano-HfO2 as a potent structural and radiative modifier, providing a novel roadmap for designing high-density, multifunctional glass-ceramic shields for advanced nuclear applications.

  AtıfScopus1·OpenAlex1

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• MakaleYalnız künye2024Scopus SJRQ1/r/munzur/1940
  A closer-look on W and Pb alloys: In-depth evaluation in elastic modulus, gamma-ray, and neutron attenuation for critical applications

  ALMisned, Ghada; Susoy, Gulfem; Sen Baykal, Duygu; Alkarrani, Hessa; Güler, Ömer; Tekin, H.O.

  This investigation assesses the gamma-ray and neutron attenuation properties of various alloys, including Pb90Cu10, A5, Manganin-R, Cu0.2Ag0.8, SA4, and W-based, to uncover efficient and cost-effective radiation shielding materials. Our study centers on alloys featuring elements such as lead, molybdenum, silver, and tungsten, selected for their unique protective qualities against radiation. Employing computational methods to evaluate critical parameters like mass attenuation coefficients, half-value layers, linear attenuation coefficients, and effective atomic numbers, transmission factor, we found the W-based alloy to exhibit exceptional shielding properties, primarily due to its tungsten content. Interestingly, this alloy also demonstrated the highest elastic modulus among the samples studied, indicating a potential synergy between an alloy's mechanical strength and its radiation shielding effectiveness. It can be concluded that alloys with higher elastic moduli not only offer better resistance to radiation-induced deformations, enhancing shielding, but also underscore the need for further research on alloys that balance performance, affordability, and environmental impact. The findings underscore the dual importance of composition and mechanical properties in advancing radiological safety and suggest continued investigation into the sustainability and practicality of effective shielding materials.

  AtıfScopus28·OpenAlex31

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• MakaleAçık Erişim2024Scopus SJRQ1/r/munzur/1796
  A comprehensive microstructural and transmission analysis on oxide dispersion-strengthened (ODS) alloys: Impact of erbium oxide (Er2O3) concentration on physical, structural, gamma-ray, and neutron attenuation properties

  Günoglu, Kadir; Güler, Seval Hale; Güler, Ömer; ALmisned, Ghada; Ozkavak, Hatice Varol; Albayrak, M. Gokhan; Akkurt, Iskender; Issa, Bashar; Tekin, H.O.

  This study explores the impact of integrating varying concentrations of Erbium Oxide (Er2O3) into Oxide Dispersion Strengthened (ODS) alloys, specifically focusing on gamma-ray and neutron attenuation properties. Utilizing a 316L stainless steel matrix, Er2O3 was methodically incorporated in concentrations ranging from 1 % to 21 % by weight. The structural and radiation attenuation properties of the resultant alloys were comprehensively analyzed using techniques such as X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and experimental gamma-ray transmission studies. The results demonstrate a significant enhancement in gamma-ray shielding with increased Er2O3 content. This enhancement is quantitatively evidenced by increased linear attenuation coefficient, elevated effective Electron Density (Neff), reduced Half-Value Layers (HVL), and higher effective atomic numbers (Zeff). These findings are crucial for nuclear applications where efficient gamma-ray shielding is paramount. Conversely, a decrease in the effective removal cross section (ΣR) for neutron attenuation was observed with higher Er2O3 concentrations. This suggests a potential compromise in neutron shielding efficiency, attributed to the dilution of neutron-absorbing base elements in the alloy. Additionally, the study reveals notable changes in the microstructural properties of the alloys, including alterations in particle size, distribution, and agglomeration, influenced by varying Er2O3 concentrations. In conclusion, this research provides valuable insights into the design of ODS alloys for nuclear radiation shielding, highlighting the balance between gamma-ray attenuation and neutron shielding properties. The study's findings contribute to the development of advanced materials for safer and more efficient nuclear technology applications.

  AtıfScopus20·OpenAlex25

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