Recently, high-entropy alloys (HEAs) have attracted significant attention due to their unique multicomponent composition and exceptional mechanical properties, such as high wear and corrosion resistance, making them superior to conventional alloys for advanced engineering applications. The effects of Al, Ti, and Mo addition on the microstructural and mechanical properties of CoCrFeNi-based HEAs were investigated. The alloys were produced via powder metallurgy and vacuum arc melting, with the addition of 2 and 3

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, Omega = 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.

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.

Recently, high-entropy alloys (HEAs) have attracted significant attention due to their unique multicomponent composition and exceptional mechanical properties, such as high wear and corrosion resistance, making them superior to conventional alloys for advanced engineering applications. The effects of Al, Ti, and Mo addition on the microstructural and mechanical properties of CoCrFeNi-based HEAs were investigated. The alloys were produced via powder metallurgy and vacuum arc melting, with the addition of 2 and 3% Al, Ti, and Mo, respectively. Scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS), and x-ray diffraction (XRD) were used to perform microstructural characterization, while microhardness and wear tests were used to evaluate mechanical performance. The addition of Al and Ti enhanced the face-centered cubic phase stability and increased the hardness by improving the lattice structure. In contrast, the addition of Mo contributed to solid solution and precipitation hardening, resulting in a simpler microstructure and superior tribological performance. Among all compositions, the alloy with 3% Mo addition exhibited the highest hardness value (approximate to 233.8 HV) and the lowest mass loss (4.3 mg) was observed, indicating a significant improvement in the wear resistance and mechanical strength. In conclusion, the addition of Ti and Mo to CoCrFeNi HEAs promotes solid solution, precipitation, and grain boundary hardening mechanisms, thereby enhancing microstructural integrity, hardness, and wear resistance. These findings suggest that such alloys are promising candidates for use as next-generation structural and tribological materials under demanding operational conditions.

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.

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 gamma-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 gamma-ray attenuation, effective atomic number, buildup behaviour, and fast-neutron removal efficiency. N1 and N3, containing multiple rareearth 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.

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.

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.

In this study, the incorporation of a high-entropy rare-earth oxide, (GdLaEuPrDyY)2O3 (RE-HEO), into a borosilicate glass matrix was investigated with the aim of improving radiation shielding performance while preserving the structural integrity of the glass. The RE-HEO was first synthesized by high-energy mechanical alloying and then introduced into the glass system at concentrations ranging from 0 to 8 wt% using a conventional meltquenching process. The structural and microstructural properties of the prepared samples were examined using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy combined with energy-dispersive spectroscopy (SEM-EDS). The analyses confirmed that the amorphous nature of the borosilicate glass was maintained and that the rare-earth elements were homogeneously distributed within the matrix. The radiation shielding performance was evaluated experimentally using Am-241, Ba-133, and Ra-226 gamma sources, and supported by theoretical calculations of key parameters including mass attenuation coefficient (MAC), half-value layer (HVL), mean free path (MFP), effective atomic number (Zeff), exposure buildup factor (EBF), and fast neutron removal cross-section (Sigma R). The results showed that increasing RE-HEO content leads to a noticeable improvement in gamma-ray attenuation. In particular, the sample containing 8 wt% RE-HEO exhibited a MAC value of 0.131 cm2/g and an HVL of 2.03 cm at 356 keV, indicating shielding performance comparable to that of conventional lead-containing glasses. In addition, irradiation tests performed using a Co-60 gamma source revealed that the amorphous structure remains stable after exposure. Overall, the findings suggest that RE-HEO-doped borosilicate glass can be considered a promising lead-free alternative for radiation shielding applications.

This research comprehensively investigates the impact of incorporating rare earth oxides -samarium oxide (Sm2O3) and lanthanum oxide (La2O3)-into a borate glassy-ceramic system enriched with tungsten oxide (WO3), with a focus on both structural characteristics and radiation shielding performance. SEM-EDS, elemental mapping, and XRD analyses conducted on the synthesized glassy-ceramic samples revealed that the incorporated rare earth oxides, Sm2O3 and La2O3, were uniformly distributed throughout the glassy-ceramic matrix. The results also confirmed that the glassy-ceramic retained its inherently amorphous structure. Moreover, the nominal doping levels of the rare earth elements were found to be in agreement with both the qualitative and quantitative results obtained from EDS measurements. Also, the gamma ray shielding parameters of synthesized glassy-ceramic samples were measured in absorption geometry with Am-241, Ba-133 and Ra-226 radioactive sources. The neutron shielding parameters were theoretically calculated. The 241Am-Be fast neutron source was used to measure the equivalent dose of neutron absorption. At an incident photon energy of 74.8 key, the mass attenuation coefficient of the tungsten oxide-enriched borate glassy-ceramic exhibited a remarkable improvement-rising by 17.98 % with the addition of 3 wt% Sm2O3 and by 11.58 % with the addition of 3 wt% La2O3. Notably, the N4 sample demonstrated a significant reduction in neutron-equivalent dose rate, reaching 19.80 % (mu Sv/h). The lead equivalent thicknesses (Pbeq) calculated at 356 key were 0.02397 cmPb for N0, 0.0391 cmPb for N1, 0.0403 cmPb for N4, and 0.0389 cmPb for N7. When benchmarked against the undoped N0 sample, the N4 and N7 compositions exhibited reductions in Pbeq values by approximately 68 % and 62 %, respectively, indicating a marked improvement in gamma shielding efficiency. Among all tested formulations, the Sm2O3-doped variant demonstrated superior gamma-ray attenuation capability relative to the La2O3-doped glassy-ceramic. Furthermore, the N4 sample achieved an impressive thermal neutron attenuation rate of 96.46 %, underscoring its strong potential as an effective dual-purpose shielding material against both thermal neutrons and ionizing gamma radiation.

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.

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.

Refractory High Entropy Alloys (RHEAs) have become an attractive alternative for radiation shielding applications due to their high mechanical strength, thermal resistance, structural stability, and compositional diversity. In this study, Cu-based composites containing 0-20 wt% RHEAs were prepared, and the crystal structure, morphological properties, and radiation shielding performance of the synthesized Cu-RHEA were investigated experimentally and theoretically. Measurements were performed using a NaI(Tl) detector system with point sources of 133Ba, 137Cs, 22Na and 60Co emitting gamma energies in the range of 0.356-1.333 MeV. In addition, theoretical calculations were carried out using the FLUKA and Phy-X/PSD, showing good agreement with the experimental data. Linear attenuation coefficient (LAC) values were found to decrease with increasing photon energy and to increase with increasing RHEA content. In the 0.356-1.333 MeV energy range, the experimental LAC values ranged from 0.7599 to 0.3818 cm- 1 for Cu-RHEA0 and from 0.9594 to 0.4221 cm- 1 for Cu-RHEA20. At 0.662 MeV, the LAC value increased from 0.5426 cm- 1 for Cu-RHEA0 to 0.6183 cm-1 for Cu-RHEA20. In terms of half-value layer (HVL), the Cu-RHEA20 sample exhibited a value of 0.729 cm at 0.356 MeV, approximately 20% lower than the 0.912 cm value of Cu-RHEA0. Compared with conventional shielding materials reported in the literature, the Cu-RHEA20 sample reached a maximum mass attenuation coefficient (MAC) of 76.279 cm2 & sdot;g- 1 at 0.015 MeV, demonstrating clear superiority over ordinary concrete with a value of 7.079 cm2 & sdot;g- 1. These findings demonstrate that increasing RHEA content improves gamma-ray attenuation performance, highlighting Cu-RHEA20 as a promising next-generation shielding material.

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 degrees 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 degrees 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.

This study addresses a fundamental materials design question for radiation-resistant superalloys: whether rareearth (RE) oxides are more effective when incorporated individually or when introduced collectively in a highentropy 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 singleoxide 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.

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.

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 key 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 gamma-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.

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 Delta Smix =12.51 J K- 1 & sdot;mol- 1 and Omega = 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.

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 (Sigma R = 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.