Özkul, İskender; Güler, Ömer; Durmus, Hasan; Camgoz, Berkay; ALMisned, G.; Yaprak, Gunseli; Tekin, H.O.

This study examines how Er2O3 and B4C additions affect the structural, microstructural, mechanical, and gamma-ray attenuation behaviour of Ni–Co–Fe–Cr–Mo high-entropy alloy composites. Five samples, labelled S0–S4, were produced by vacuum arc melting with different single and combined reinforcement contents. Thermodynamic calculations showed that the metallic matrix meets the general conditions expected for solid-solution HEA formation. XRD results indicated that an FCC-based matrix remained dominant in all samples. Reflections related to Er2O3 were identified in the Er2O3-containing compositions, while several weak secondary reflections could not be assigned with certainty because of their low intensity and peak overlap. SEM-EDS analysis confirmed the presence of Er-, O-, B-, and C-containing regions and also revealed local compositional variations within the microstructure. The reinforcement additions produced a clear increase in microhardness, with the highest value of 693 ± 51 HV0.5 obtained for the hybrid-reinforced S3 sample. Gamma-ray attenuation was measured at 276, 302, 356, and 383 keV using a high-purity germanium (HPGe) detector under narrow-beam condition. S4 showed the lowest nominal transmission factor at most energies at its actual sample thickness. However, after correcting for thickness using the Beer-Lambert relationship, S2 generally showed the highest nominal linear attenuation coefficient, while S4 gave closely comparable values at several energies. Some of the differences between samples were within the propagated counting uncertainties and were therefore interpreted with caution. Overall, the results show that the composition giving the highest hardness does not necessarily provide the strongest thickness-normalized gamma-ray attenuation. The attenuation behaviour is influenced by several factors, including reinforcement composition, sample thickness, density, phase distribution, microstructural heterogeneity, and measurement uncertainty. These findings highlight the need to optimize reinforced HEA composites according to the specific mechanical and radiation-related property being targeted.

İncele

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.

İncele

Özkul, İskender; Güler, Ömer; Kavaz, E.; Kalay, Ece; Güler, Seval Hale; ALMisned, Ghada; Tekin, H.O.

This study investigates three newly designed Ti-Zr-Hf-based high-entropy alloys such as TiZrHfGdSm (N1), TiZrHfEr (N2), and TiZrHfGdEuB (N3), with the aim of understanding how selected rare-earth and boron additions influence microstructural evolution and dual γ-ray/fast-neutron shielding performance. All alloys were synthesized by arc melting and evaluated through thermodynamic modelling, X-ray diffraction, scanning electron microscopy with elemental mapping, and mixed-field attenuation measurements. The results show that each composition forms an HCP-type solid-solution matrix with composition-dependent lattice distortion and secondary phase formation. Among the studied systems, the Er-modified alloy N2 develops the most spatially uniform elemental distribution and demonstrates the most balanced combination of γ-ray attenuation, effective atomic number, buildup behaviour, and fast-neutron removal efficiency. N1 and N3, containing multiple rare-earth elements and, in the case of N3, boron-induced borides, exhibit distinct grain features and provide valuable insights into how multi-element additions shape photon and neutron interaction pathways. Comparative examination confirms that shielding performance in these HEAs is governed by the interplay of elemental cross sections, density, and microstructural uniformity. The findings highlight Ti-Zr-Hf-RE(B) alloys as promising platforms for multifunctional radiation-shielding materials and provide a compositional framework for future optimization in nuclear, medical, and aerospace applications.

AtıfScopus2·OpenAlex2

İncele

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

İncele

Yayla, Nihal; Albayrak, M. Gökhan; Güler, Ömer; Sen Baykal, Duygu; Alkarrani, Hessa; ALMisned, Ghada; Tekin, H.O.

Type 316L stainless steel (316L-SS) is widely recognized for its exceptional corrosion resistance, making it a preferred material in various industries. However, conventional stainless steel materials are inadequate for radiation shielding applications. While oxide dispersion-strengthened alloy composites with a 316L-SS matrix have been extensively studied in the literature for their mechanical creep properties, their radiation shielding capabilities remain insufficiently explored. This study investigates the potential of samarium oxide (Sm2O3) doped to improve the structural, physical, mechanical, and radiation shielding properties of 316L-SS composites. Samples containing 1%, 5%, 10%, and 20% Sm2O3 by weight were synthesized and extensively characterized using X-ray diffraction and scanning electron microscopy. These analyses revealed enhanced homogeneity and refined grain structure with increasing Sm2O3 content. Gamma-ray and neutron shielding properties demonstrated significant improvements, particularly in composites with 20% Sm2O3 reinforcement, as evidenced by lower half-value layer and mean free path values, along with an increased fast neutron removal cross section. However, a trade-off was observed between radiation shielding performance and mechanical properties: As the Sm2O3 content increased, the elastic modulus decreased, indicating reduced stiffness due to the incorporation of Sm2O3. This trade-off suggests that while Sm2O3 reinforcement effectively enhances radiation shielding, it may not be ideal for structural applications requiring high mechanical strength. Nevertheless, these findings highlight the potential of Sm2O3-doped 316L-SS composites for nonstructural radiation protection systems, particularly in applications where improved shielding performance is prioritized over mechanical stiffness.

AtıfScopus5·OpenAlex7

İncele

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.

AtıfScopus1·OpenAlex1

İncele

Güler, Ömer; Şimşek, Telem; Şimşek, Tuncay; Evin, Ertan; Baykal, Duygu Sen; ALMisned, Ghada; Tekin, H.O.

In this study, a novel FeCoNiMnCu HEA was synthesized via mechanical alloying and exhibited a single-phase face-centered cubic (FCC) structure with a crystallite size of 11.7 nm and a lattice strain of 0.81 %. Magnetic characterization revealed soft ferromagnetic behavior with a saturation magnetization of 32 emu/g at 300 K, increasing to 53 emu/g at 10 K. The alloy demonstrated excellent gamma-ray attenuation, with lower half-value layer (HVL) and mean free path (MFP) values than conventional shielding materials. Notably, its fast neutron removal cross-section (ΣR = 0.1654 cm−1) outperformed standard materials such as B4C, graphite, and water in the fast neutron energy range. These findings underline the multifunctional performance of FeCoNiMnCu HEA, highlighting its strong potential for use in advanced nuclear reactor components and radiation shielding technologies.

AtıfScopus10·OpenAlex6

İncele

Özkul, İskender; Güler, Ömer; Camgoz, Berkay; ALMisned, Ghada; Yaprak, Gunseli; Tekin, H.O.; Durmus, Hasan

This study investigates the structural, mechanical, and experimental gamma-ray attenuation properties of Fe-Co-Ni-Cr-W high-entropy alloy (HEA) composites reinforced with varying concentrations of Dy2O3 and B4C. A series of samples (S0-S4) was synthesized via vacuum arc melting to evaluate the synergistic effects of rare-earth oxide and carbide additions on a stable multi-component matrix. Thermodynamic assessments confirmed that the base alloy aligns with solid-solution formation criteria (1.61R configurational entropy, Ω = 10.33), which was experimentally validated by XRD patterns revealing a consistent FCC crystal structure across all compositions. SEM-EDS mapping further verified the successful integration of reinforcements as discrete secondary phases within the HEA matrix. Mechanical characterization showed that ceramic incorporation significantly enhances the hardness of the monolithic HEA, with the hybrid-reinforced S3 sample achieving a peak value of 628 HV. This improvement is attributed to the combined effects of oxide dispersion strengthening and microstructural refinement induced by B4C. Experimental gamma-ray transmission tests, conducted using a high-purity germanium (HPGe) detector in the 276-383 keV energy range, demonstrated that the S3 configuration provides the most efficient shielding performance, characterized by the lowest transmission factors. Interestingly, the results suggest that beyond an optimal threshold, increased reinforcement loading, as seen in S4 sample, may lead to minor performance trade-offs due to phase distribution dynamics. The findings highlight that the development of multifunctional HEA-based shields requires a delicate balance between reinforcement volume fraction and microstructural homogeneity to maximize both structural and shielding efficiency.

AtıfOpenAlex1

İncele

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

This study investigates the effects of holmium oxide (Ho2O3) microparticle reinforcement on the structural, physical, and radiation shielding properties of borotellurite glasses with compositions ranging from 0 to 12 mol% Ho2O3. X-ray diffraction and TEM analyses confirmed the retention of amorphous structure across all samples, with localized short-range ordering observed at higher Ho contents. Glass density increased from 4.598 to 5.202 g/cm3 with increasing Ho2O3, while molar volume expanded from 27.94 to 30.61 cm3/mol, and oxygen packing density decreased from 0.605 to 0.551 g/cm3, indicating network expansion due to the substitution of lighter Li + ions by heavier Ho3+. Gamma-ray shielding properties significantly improved with Ho incorporation. At 81 keV, the linear attenuation coefficient increased from 8.33 to 13.70 cm−1, and the mass attenuation coefficient improved from 2.066 to 2.735 cm2/g. Moreover, effective atomic number rose from 44.9 to 52.5 and half-value layer decreased by 20.5% at 383 keV, and buildup factors dropped by up to 34% at 0.5 MeV. Neutron dose absorption improved, and the fast neutron removal cross-section increased from 0.1066 to 0.1113 cm−1. These results confirm that Ho2O3 contributes as a highly effective multifunctional dopant, significantly enhancing both gamma-ray and neutron shielding performance of borotellurite glasses, one of the most promising glass systems for advanced radiation protection applications.

AtıfScopus1·OpenAlex1

İncele

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

This study investigates the structural, physical, and radiation-shielding properties of nano-Gd2O3-reinforced lithium borotellurite glasses with the composition 50TeO2-30B2O3-(20-x)Li2O-xGd2O3 (x= 0-10 mol %). X-ray diffraction and transmission electron microscopy confirmed the fully amorphous nature of the glasses and the homogeneous distribution of nanoscale Gd clusters. Density increased from 4.03 to 4.77 g/cm3, accompanied by compositional shifts, decreasing boron and increasing oxygen and tellurium contents, indicating enhanced structural compactness and electron density. Gamma-ray attenuation measurements revealed a 74 % increase in the linear attenuation coefficient from 8.33 to 14.53 cm−1 at 81 keV and a nearly 27 % reduction in the half-value layer from 1.21 to 0.89 cm. Effective atomic number values remained highest for Gd(n)10 across the photon energy range investigated. Experimental neutron dose measurements showed absorption improvements from 37.66 % to 51.91 %, while the effective removal cross-section increased from 0.1066 to 0.1096 cm−1, outperforming water, B4C, and graphite. Compared with the Gd-doped zinc borotellurite glasses reported in the literature, the present lithium-based system exhibited higher densification and superior dual γ-neutron attenuation. These results demonstrate that controlled nano-Gd2O3 integration into the lithium borotellurite matrix yields a stable, lead-free amorphous material with outstanding radiation-shielding efficiency for advanced photonic and nuclear applications.

AtıfScopus3·OpenAlex3

İncele

Simsek, Tuncay; Simsek, Telem; Chattopadhyay, Arun K.; Avar, Barış; Yakin, Alican; Guler, Seval Hale; Almisned, Ghada; Sen Baykal, Duygu; Tekin, H.O.

In this study, mechanically alloyed Fe70Nb10V10B10, Co70Nb10V10B10, Ni70Nb10V10B10, and (FeCoNi) 70Nb10V10B10 high-entropy alloys were successfully synthesized, and their structural, magnetic, and radiation shielding properties were systematically investigated. Structural analysis revealed that Fe favored bcc phase formation, while Co and Ni stabilized fcc structures; the equiatomic alloy resulted in a single-phase fcc solid solution with the smallest crystallite size (2.1 nm). All samples exhibited soft ferromagnetic behavior, with the Fe-based alloy achieving the highest saturation magnetization (120 emu/g), and the (FeCoNi) 70Nb10V10B10 alloy displaying the lowest coercivity. Among all compositions, Co70Nb10V10B10 demonstrated the best gamma and neutron shielding performance, showing the highest linear attenuation coefficient and fast neutron removal cross-section. The equiatomic alloy also exhibited well-balanced and stable shielding behavior. These findings position Co70Nb10V10B10 as a promising candidate for multifunctional applications requiring both efficient radiation protection and favorable magnetic properties.

AtıfScopus1

İncele

Güler, Ömer; Güler, Seval Hale; Özkul, İskender; ALMisned, Ghada; Sen Baykal, Duygu; Tekin, H.O.

Spinel high-entropy oxides (HEOs) can stabilize multiple transition-metal cations within a single lattice, yet their radiation-interaction behavior is scarcely explored. Here, a (FeNiCoCrMn)3O4 spinel HEO was produced via an alloy-to-oxide route: 40 h mechanical alloying of equiatomic FeNiCoCrMn powders followed by mechano-oxidation (1000 °C/3 h) and high-energy grinding. HEA-derived thermodynamic metrics were used to rationalize the stability of the equiatomic metallic precursor prior to mechano-oxidation, rather than to directly predict the formation of the final oxide phase. XRD evidenced progressive amorphization of the HEA and its conversion to a crystalline spinel oxide, while SEM–EDS confirmed homogeneous elemental distribution. XPS indicated a defect-rich, multivalent surface (Co2+/Co3+, Cr3+/Cr6+, Fe3+, mixed Mn states, Ni2+) with lattice oxygen and vacancy-related components. Moreover, the spinel oxide showed higher linear attenuation coefficients than 316L stainless steel, Inconel-718, and several lightweight Al-based entropy alloys, yielding lower HVL values, especially at low energies. Zeff exhibited the expected energy dependence and exceeded Al-dominant alloys across the spectrum. EBF/EABF at 1 and 40 mfp displayed Compton-region peaks and strong depth effects, consistent with attenuation behavior. It can be concluded that a (FeNiCoCrMn)3O4 spinel high-entropy oxide, produced via an alloy-to-oxide transformation route, exhibits structurally stable and compositionally homogeneous characteristics together with favorable gamma-ray attenuation behavior.

İncele

Özkul, İskender; Kalay, Ece; Güler, Ömer; Karaduman, Oktay; Canbay, Canan Aksu; Hameed, Louis Ibrahim; Almisned, Ghada; Baykal, Duygu Sen; Tekin, H.O.

This study investigates the effect of 1 at.% rare-earth (RE = Sm, Gd, Dy) addition on the structural, mechanical, magnetic, and radiation shielding properties of CoFeNiMnTi high-entropy alloys produced by arc melting. X-ray diffraction results reveal an FCC-dominant structure accompanied by secondary Laves-type phases, with increased phase complexity observed in Gd- and Dy-containing alloys. Mechanical evaluation shows a significant hardness enhancement, reaching 581 HV for Gd and 548 HV for Dy, compared to 447 HV for the reference alloy. Magnetic measurements indicate soft-ferromagnetic behaviour for all compositions, with magnetization increasing in the order S0<S1<S2<S3, highlighting the strong influence of Dy on magnetic response. Elemental mapping confirms a homogeneous distribution with minor local compositional variations contributing to phase evolution. Thermodynamic analysis suggests that rare-earth addition increases lattice distortion and chemical complexity without strongly differentiating among RE types. In terms of radiation shielding, linear attenuation coefficients and effective atomic number values demonstrate improved gamma-ray attenuation, particularly at low energies, with Dy exhibiting the highest performance. In contrast, fast neutron removal cross section values remain nearly unchanged, indicating limited sensitivity to dilute RE addition. It can be concluded that the incorporation of Dy results in the most balanced multifunctional performance, whereas Gd primarily enhances mechanical strength, emphasizing the importance of rare-earth selection in the design of high-entropy alloys for radiation-related applications.

İncele

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.

İncele

Güler, Ömer; Güler, Seval Hale; Özkul, İskender; Baykal, Duygu Sen; Tekin, H.O.; ALMisned, Ghada

A spinel-structured high-entropy alloy-oxide (HEAO) with the nominal composition (Fe30Cr30Mn20Ni10V10)3O4 was synthesized via mechanical alloying followed by thermo-mechanical oxidation X-ray diffraction indicated the formation of a predominantly spinel-type cubic oxide phase after oxidation, with the observed reflections being consistent with the Fd-3m spinel structure, while SEM-EDS mapping showed a homogeneous cation distribution at the examined scale. XPS analysis revealed mixed valence states of Fe2+/Fe3+, Cr3+/Cr4+, Mn3+/Mn4+, Ni2+/Ni3+, and V4+/V5+. Thermodynamic parameters supported phase stability, with ΔSmix = 12.51 J K−1·mol−1 and Ω = 2.68. Gamma-ray attenuation properties were evaluated over 0.015-15 MeV. The linear attenuation coefficient decreased from 193.685 cm−1 at 0.015 MeV to 0.309 cm−1 at 1 MeV and stabilized near 0.137 cm−1 at 15 MeV. Correspondingly, the half value layer increased from 0.004 cm to 5.068 cm across the same energy range. The effective atomic number decreased from 24.58 at 0.015 MeV to approximately 15.37 at 1 MeV, followed by a moderate increase to 17.71 at 15 MeV. Comparative analysis with commercial stainless steel, titanium alloys, nickel-based superalloys, ferro-boron systems, and lightweight entropy alloys demonstrated that the synthesized HEAO exhibits intermediate yet stable attenuation performance, positioning it between low-density Al-based systems and high-density Ni-rich alloys. It can be concluded that the alloy-to-oxide strategy enables the production of a structurally stable spinel HEAO with consistent and competitive gamma-ray attenuation behaviour across a broad photon energy spectrum.

AtıfScopus1·OpenAlex1

İncele

Güler, Ömer; Özkul, İskender; Almisned, Ghada; Sen Baykal, Duygu; Alkarrani, Hessa; Kilic, G.; Mesbahi, A.; Tekin, H.O.

This study explores the development and characterization of 18 novel ZrWNb[(X)(Y)] (where XY are Hf, Ta, Mo, V, Ti) refractory high entropy alloys (RHEAs) designed to enhance mechanical robustness, thermodynamic stability, and radiation shielding effectiveness. Through a rigorous analysis, we evaluated the elastic modulus, entropy, and enthalpy of mixing, atomic size difference, valence electron concentration, and the omega parameter to understand the alloys’ phase behavior and structural integrity. Our findings revealed a broad range of elastic modulus values, indicating diverse mechanical adaptability suitable for high-stress applications. The thermodynamic assessment highlighted several RHEAs with favorable phase stability, particularly ZrWNbTaHf and ZrWNbTiTaHf, which are poised for high-performance usage due to their balanced mixing entropy and enthalpy. This study also benchmarks the RHEAs against conventional alloys, with sample R1 exhibiting the lowest fast neutron effective removal cross section, underscoring its superior neutron shielding capabilities. Additionally, R1 demonstrated exceptional photon attenuation, as evidenced by its competitive half-value layer performance across an extensive energy spectrum. Collectively, these results position R1 as a standout candidate, offering a significant advancement in materials science for applications demanding stringent radiation shielding, such as in nuclear reactor environments and space exploration.

AtıfScopus4·OpenAlex5

İncele

Tekin, H.O.; Yayla, Nihal; Albayrak, M.Gökhan; Güler, Ömer; Baykal, Duygu Sen; Alkarrani, Hessa; ALMisned, Ghada

316L stainless steel is widely utilized in various industries due to its excellent corrosion resistance, mechanical strength, and biocompatibility, making it a preferred material for applications in nuclear filed. However, enhancing its radiation shielding and mechanical properties through reinforcement strategies, such as the addition of high-Z materials like Europium(III) oxide, is crucial for extending its functionality in high-radiation environments, where improved performance is essential for safety and durability. In this study, 316L stainless steel composites reinforced with varying amounts of Eu2O3 (1%, 5%, 10%, and 20%) were synthesized and investigated for their structural, mechanical, and radiation shielding properties. X-ray diffraction (XRD) analysis revealed that the face-centered cubic (FCC) structure of the steel matrix was preserved up to 5% Eu2O3 reinforcement, while higher concentrations led to phase formation and crystallographic changes. Scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analysis showed uniform element distribution at low reinforcement levels, with particle clustering at 20% Eu2O3. Transmission factors (TFs) were evaluated using PHITS simulations for photon energies of 0.662 MeV, 1.1732 MeV, and 1.3325 MeV. The 20% Eu2O3 composite exhibited the lowest TF and highest attenuation properties, confirmed by mass and linear attenuation coefficients. Elastic modulus values decreased from 224.46 GPa in pure 316L to 189.26 GPa with 20% Eu2O3 reinforcement, reflecting the inverse relationship between mechanical stiffness and radiation shielding performance. Benchmarking against other shielding materials demonstrated superior performance of the Eu2O3-reinforced steel in gamma-ray attenuation. The 20% Eu2O3 composite shows strong potential for applications in nuclear radiation shielding where attenuation efficiency is prioritized over mechanical properties.

AtıfScopus13·OpenAlex14

İncele

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

This study investigates the influence of high entropy oxide (HEO) and high entropy alloy oxide (HEAO) dopants on the structural, optical, and radiation shielding properties of zinc-borate glasses. Two synthesis routes were employed through direct mechanical alloying of five rare-earth oxides such as Sm2O3, Ho2O3, Er2O3, Yb2O3, Gd2O3 to form (SmHoErYbGd)2O3 HEO, and mechanical alloying of the corresponding rare-earth metals followed by oxidation to produce HEAO of the same elemental composition. The central hypothesis proposed that the dopant structure and oxygen coordination, not just elemental presence, critically influence the on characteristic behaviors in terms of radiation attenuation. Structural analyses confirmed that HEAO-doped glasses exhibit more homogeneous, amorphous networks. Optical characterizations revealed red-shifted absorption edges and lower Urbach energies in HEAO samples, indicating reduced disorder. HEAO-doped glasses showed superior gamma-ray shielding, with higher linear attenuation coefficients and lower half-value layers than HEO or undoped samples. Most notably, HEAO glass achieved the highest fast neutron removal cross-section, surpassing water, graphite, and B4C. These findings demonstrate that rare-earth high entropy alloy oxides offer a structurally optimized pathway for designing next-generation multifunctional glasses for radiation-related applications.

AtıfScopus9·OpenAlex8

İncele

ALMisned, Ghada; Susoy, Gulfem; Baykal, Duygu Sen; Alkarrani, Hessa; Güler, Ömer; Issa, Shams A.M.; Zakaly, Hesham M.H.; Tekin, H.O.

This study explores the gamma-ray and neutron shielding properties and mechanical performance of eight Fe-based alloys with varying elemental compositions and densities. Different parameters such as mass attenuation coefficients, linear attenuation coefficients, half-value layer, tenth-value layer, mean free path, fast neutron removal cross-sections, transmission factors were analysed using PHITS and Phy-X/PSD codes. Moreover, elastic modulus values were calculated for each alloy sample. Our results reveal that the S9 alloy, with high density and tungsten contribution, exhibited superior shielding and mechanical properties, achieving the lowest TF, HVL, and TVL values. In contrast, the low-density S1 alloy performed weakest, reflecting its lighter elemental composition. Intermediate alloys like MAR-302 and Cupero-Nickel showed balanced performance, suitable for moderate shielding needs. Strong correlations between elemental compositions, particularly high-Z elements like tungsten and boron, and shielding efficiency were observed. It can be concluded that optimizing elemental composition and density is critical for designing alloys with enhanced multifunctional properties.

AtıfScopus3·OpenAlex2

İncele

Karaduman, Oktay; Kalay, Ece; Ozkul, Iskender; Kurgun, Mehmet Ali; Canbay, Canan Aksu; Guler, Omer; ALMisned, Ghada; Baykal, Duygu Sen; Tekin, H.O.

A novel Cu-based high-temperature shape memory alloy (HTSMA) with the composition 70.84Cu–23.80Al–4.14Mn–1.22Fe (at. %) was successfully synthesized via arc melting in this study. The effects of thermal aging duration on the alloy’s martensitic transformation behavior, shape memory effect (SME), and microstructural evolution were systematically investigated. Six samples were prepared from the as-cast ingot: one was homogenized in the β-phase region and quenched into ice-brine to induce a martensitic structure, while five others were subsequently aged at 350 ℃ for varying durations and air-cooled. Thermal and structural characterizations were conducted. These included differential scanning calorimetry (DSC), X-ray diffraction (XRD), energy-dispersive spectroscopy (EDS), and optical microscopy. Prolonged aging altered transformation temperatures and reduced both enthalpy and entropy values. It also promoted the formation of observed precipitates, vacancies, and coarsened 2H martensites. Prolonged aging altered the microstructure and thermal response, leading to partial SME degradation. Additionally, the alloy’s gamma-ray and fast neutron shielding parameters were theoretically estimated using simulation software to explore its potential functional scope. The calculated results indicate that the CuAlMnFe HTSMA is predicted to exhibit favorable attenuation performance across a wide energy spectrum, with appropriate values of mass attenuation coefficient (MAC) and half-value layer (HVL). In particular, the fast neutron removal cross-section was calculated as 0.139 cm−1, which is significantly higher than those of water (0.1023 cm−1), graphite (0.0773 cm−1), and B4C (0.0714 cm−1). In conclusion, the CuAlMnFe HTSMA developed in this study offers a unique profile combining tailorable shape memory behavior with a computationally predicted potential for nuclear radiation shielding. These properties offer novel insights into the alloy’s potential for applications in high-radiation environments that require both mechanical actuation and radiation protection, pending experimental validation of its shielding performance.

AtıfScopus1·OpenAlex1

İncele