Yazarlar
- Tekin, H.O.(5)
- ALMisned, Ghada(4)
- Güler, Ömer(3)
- Özkul, İskender(3)
- Almisned, Ghada(2)
- Baykal, Duygu Sen(2)
- Durmus, Hasan(2)
- Güler, Seval Hale(2)
- Kilic, Gokhan(2)
- Sen Baykal, Duygu(2)
- Akkus, Baki(1)
- Aksu Canbay, Canan(1)
- Alan, Hatice Yilmaz(1)
- Albayrak, M. Gökhan(1)
- Alkarrani, Hessa(1)
- Birdogan, Selçuk(1)
- Bülbül, Zeynel Abidin(1)
- Guler, Omer(1)
- Guler, Ömer(1)
- Gökhan Albayrak, M.(1)
- Gül, Ali Oktay(1)
- Ilik, E.(1)
- Ilik, Erkan(1)
- Kalay, Ece(1)
- Karaduman, Oktay(1)
- Kavaz, Esra(1)
- Kilic, G.(1)
- Oktik, Sener(1)
- Perişanoğlu, Esra Kavaz(1)
- Saltık, Sevda(1)
- Susam, Lidya Amon(1)
- Tekin, Huseyin Ozan(1)
- Yayla, Nihal(1)
- Yilmaz, Ayberk(1)
- Şimşek, Telem(1)
Yayınlar
- MakaleYalnız künye2026Scopus SJRQ2Compositional control of structural, magnetic, and gamma-ray attenuation properties in rare-earth substituted Ho-based double perovskite oxides synthesized via mechanical alloying and oxidation
Özkul, İskender; Kalay, Ece; Güler, Seval Hale; Karaduman, Oktay; Şimşek, Telem; Bülbül, Zeynel Abidin; Aksu Canbay, Canan; Sen Baykal, Duygu; ALMisned, Ghada; Tekin, H.O.
Rare-earth substitution provides a route for tailoring the structural, magnetic, and gamma-ray attenuation behaviour of Ho-based Co-Mn double perovskites; however, the combined effects of rare-earth ionic size, magnetic character, and substitution level remain insufficiently understood. In this study, Ho1.5La0.5CoMnO6, Ho1.2Er0.8CoMnO6, Ho1.3Sm0.7CoMnO6, and Ho2CoMnO6 were synthesized through a two-step route involving mechanical alloying to obtain precursor powders, followed by annealing at 1000 °C in air to promote oxidation and double-perovskite phase formation. Their structural, thermal, surface-chemical, magnetic, and gamma-ray attenuation properties were examined by X-ray diffraction, thermal analysis, X-ray photoelectron spectroscopy, SEM-EDS, vibrating-sample magnetometry, and theoretical shielding calculations based on half-value layer (HVL) and transmission factor (TF) parameters. The XRD patterns were consistent with predominantly monoclinic P21/n type double-perovskite structures, while weak additional reflections suggested possible minor secondary phases. SEM-EDS showed homogeneous elemental distributions, and XPS analysis indicated Co2+ dominated and mixed Mn-valence characteristics in the spectra where reliable component analysis was possible. All compositions exhibited a low-temperature ferromagnetic-like field response but did not reach magnetic saturation at 3 T. Ho2CoMnO6 and Ho1.3Sm0.7CoMnO6 showed the highest field-dependent magnetization values at 10 K, whereas Ho1.2Er0.8CoMnO6 displayed the lowest response. The theoretical gamma-ray attenuation calculations showed clear composition-dependent differences. At 0.662 MeV, the HVL values were 1.0650, 0.9972, 1.0438, and 0.9967 cm for Ho1.5La0.5CoMnO6, Ho1.2Er0.8CoMnO6, Ho1.3Sm0.7CoMnO6, and Ho2CoMnO6, respectively. At the same photon energy and a thickness of 1.0 cm, the corresponding TF values were 0.0896, 0.0858, 0.0882, and 0.0860. Thus, Ho1.2Er0.8CoMnO6 and Ho2CoMnO6 exhibited the lowest HVL and TF values among the investigated compositions. The shielding calculations identified Ho1.2Er0.8CoMnO6 and Ho2CoMnO6 as the most effective attenuators, with lower HVL and TF values across the investigated energy range. These results show that rare-earth substitution enables compositional tuning of magnetic and theoretical gamma-ray attenuation behaviour, with the observed trends reflecting the combined influence of rare-earth ionic size, magnetic character, substitution level, and valence-state complexity.
- MakaleAçık Erişim2026Scopus SJRQ1Comparative assessment of individual rare-earth oxides and high-entropy rare-earth oxides reinforcements on the structural, physical, and radiation transmission properties of Inconel 718
Gül, Ali Oktay; Gökhan Albayrak, M.; Güler, Ömer; Özkul, İskender; Baykal, Duygu Sen; Almisned, Ghada; Tekin, H.O.
This study addresses a fundamental materials design question for radiation-resistant superalloys: whether rare-earth (RE) oxides are more effective when incorporated individually or when introduced collectively in a high-entropy rare-earth oxide (HE-RE2O3) form. In this context, Inconel 718 (IN718) composites were reinforced with single RE2O3 phases such as Sm2O3, Tm2O3, Er2O3, Yb2O3, Eu2O3, and La2O3 at 10 wt% and with a mechanically alloyed HE-RE2O3 phase at 1-20 wt%. Structural analyses confirmed the formation of a single-phase HE-RE2O3 with a cubic bixbyite structure and its stable integration into the IN718 matrix. Gamma-ray shielding properties were systematically evaluated over a wide photon energy range. The HE-RE2O3 reinforced samples, particularly at higher loadings, exhibited consistently higher mass and linear attenuation coefficients, elevated effective atomic numbers, reduced half-value layers, and lower buildup factors compared to both the base alloy and single-oxide reinforced counterparts, demonstrating a clear collective attenuation effect. Fast neutron removal cross sections showed more moderate variations, reflecting the dominance of neutron scattering and mass-dependent interaction mechanisms rather than atomic number effects. It can be concluded that incorporating RE elements through a high-entropy oxide configuration provides a more effective and collective compositional contribution for enhancing the radiation shielding performance of IN718 than adding RE oxides individually, offering a promising pathway for advanced nuclear and radiation-relevant applications.
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İncele - MakaleYalnız künye2026Scopus SJRQ2High-entropy rare-earth tungstate (PrEuYLaSm)2(WO4)3: Synthesis, physical, structural evolution and shielding properties
Durmus, Hasan; Özkul, İskender; Güler, Ömer; Güler, Seval Hale; Baykal, Duygu Sen; ALMisned, Ghada; Tekin, H.O.
In this study, a novel high-entropy rare-earth tungstate, (PrEuYLaSm)2(WO4)3, was synthesized by high-energy ball milling followed by calcination, and its structural, microstructural, thermal, gamma-ray, and neutron shielding properties were systematically investigated. X-ray diffraction results revealed that ball milling induced partial amorphization of the initial oxide mixture, while calcination at 1100 °C promoted the formation of a single-phase monoclinic A2W3O12-type structure without detectable secondary phases. SEM-EDS mapping showed the homogeneous distribution of Pr, Eu, Y, La, Sm, W, and O throughout the synthesized material. Differential thermal analysis showed sequential desorption, crystallization, and structural ordering processes, together with the absence of sharp decomposition up to 1100 °C, indicating good thermal stability. Radiation shielding evaluation demonstrated that the synthesized high-entropy tungstate exhibited strong gamma-ray attenuation performance, with high mass attenuation coefficient values, low half-value layer values, and stable effective atomic number behaviour over a wide photon energy range. Although some individual oxides showed superior performance at specific energies, the high-entropy composition provided a more balanced shielding response overall. In neutron shielding, the material showed competitive fast neutron removal capability among oxide systems. It can be concluded that the multifunctional potential of (PrEuYLaSm)2(WO4)3 for competitive high-temperature and radiation shielding applications.
- MakaleAçık Erişim2025Scopus SJRQ2Dual-effect of Holmium(III) oxide and Boron Carbide reinforcement on physical, microstructural evolution and gamma-ray shielding performance of 316L-SS
Yayla, Nihal; Albayrak, M. Gökhan; Güler, Ömer; Almisned, Ghada; Sen Baykal, Duygu; Alkarrani, Hessa; Kilic, Gokhan; Tekin, Huseyin Ozan
This study provides one of the first comprehensive evaluations of 316L stainless steel composites reinforced with 10 wt.% B4C and varying concentrations of Ho2O3, proposing a new compositional design for simultaneous structural enhancement and dual gamma-neutron shielding optimization. XRD analysis confirmed the predominance of the austenitic phase with minor martensitic peaks at higher Ho2O3levels. SEM and EDX results revealed uniform dispersion and improved densification with increasing oxide content. The 316L-B4C-20%Ho2O3composite exhibited the highest mass attenuation coefficient (0.8953 cm2/g) and linear attenuation coefficient (6.73 cm−1) at 0.1 MeV, demonstrating superior gamma-ray shielding capability. The effective electron density increased from 2.86 × 1023to 5.82 × 1023electrons/cm³, while the energy absorption buildup factor (EABF) showed a consistent decrease with higher oxide concentrations. Although a slight reduction in fast neutron removal cross-section was observed, the composite maintained satisfactory neutron attenuation performance. Overall, the findings indicate that the 316L-B4C-20%Ho2O3system offers a promising balance between structural stability and dual radiation protection, making it a strong candidate for next-generation nuclear shielding materials.
AtıfScopus1İncele - MakaleYalnız künye2025Scopus SJRQ2Nanoarchitectonics and radiation mitigation in Sm2O3-doped lithium borotellurite glass systems: From amorphous harmony to localized order
Kilic, G.; Durmus, Hasan; Birdogan, Selçuk; Ilik, E.; Perişanoğlu, Esra Kavaz; Saltık, Sevda; Guler, Ömer; ALMisned, Ghada; Tekin, H.O.
In this study, a novel series of nano-Sm2O3-doped lithium borotellurite glasses was synthesized and systematically investigated in terms of their structural, physical, and radiation shielding characteristics. X-ray diffraction confirmed the amorphous nature of all samples, while transmission electron microscopy revealed progressive nanoarchitectural refinement and particle growth with increasing Sm2O3 content, from uniformly dispersed nanodomains to dense agglomerates exhibiting short-range crystalline ordering. Energy-dispersive X-ray spectroscopy and elemental mapping validated the homogeneous incorporation of boron, oxygen, tellurium, and samarium throughout the glass matrix without phase separation. Gamma-ray shielding evaluations showed enhanced mass attenuation coefficients and reduced half-value layers, particularly in the Sm(n)8 sample, with significant performance gains at lower photon energies. Neutron shielding assessments further indicated elevated macroscopic removal cross-section values and dose attenuation, affirming the compositional benefit of Sm2O3 for fast neutron mitigation. It can be concluded that nano-Sm2O3 incorporation would play a multifunctional role on structural and radioprotective properties in addition to morphostructural features of lithium borotellurite glasses.
AtıfScopus5OpenAlex6İncele - MakaleYalnız künye2025Scopus SJRQ2Exploring the gamma-ray shielding performance of boron-rich high entropy alloys
Alan, Hatice Yilmaz; Guler, Omer; Yilmaz, Ayberk; Susam, Lidya Amon; Kavaz, Esra; Kilic, Gokhan; Ilik, Erkan; Oktik, Sener; Akkus, Baki; ALMisned, Ghada
High entropy alloys (HEAs) are innovative materials combining multiple principal elements, known for their exceptional properties and wide-ranging applications. This study assesses the gamma-ray shielding capacity of twelve boron-based HEAs through advanced computational methods. Key parameters in terms of understanding the material's ability to reduce radiation intensity, specifically half-value layer (HVL) and tenth-value layer (TVL); its capacity to absorb or scatter photons, including mass attenuation coefficient (MAC) and linear attenuation coefficient (LAC); and other related factors such as equivalent atomic number (Zeq), effective atomic number (Zeff), effective electron density (Neff), mean free path (MFP), and fast neutron removal cross-section (FNRCS) were calculated for photon energies between 0.015 and 15 MeV using the computational method Phy-X/PSD (Photon Shielding and Dosimetry). Additionally, the interaction of alpha particles and protons with these alloys was assessed by calculating energy deposition KERMA (Kinetic Energy Released per Unit Mass) and mass stopping power (MSP) using PAGEX (interaction of protons, alpha, gamma rays, electrons, and X-rays with matter) software, while SRIM (Stopping and Range of Ions in Matter) was employed to estimate particle penetration depths. Electron interactions were evaluated using ESTAR (Stopping Power and Range Tables for Electrons) for stopping power and penetration depth. Among the alloys, Sample 10, S10, (Zr10.8%-Hf21.3%-Nb11.0%-Ta21.6%-W22.0%-B13.1%) exhibited efficient shielding properties due to its high density and interaction characteristics. It can be concluded that boron-based HEAs with optimized compositions and high densities demonstrate significant potential for advanced radiation protection applications.
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