Yazarlar

  • MakaleAçık Erişim2026Scopus SJRQ1
    Comparative 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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  • MakaleAçık Erişim2026Scopus SJRQ1
    Comparative and systematically analysis of the effects of single and high-entropy rare earth oxide additives on the some physical properties and radiation shielding properties of copper composites

    Kanca, Muhammed Sait; Yılmaz, Demet; Tasgın, Yahya; Kök, Mediha; Güler, Seval Hale

    In this study, the effects of rare earth oxides (Gd₂O₃, La₂O₃, Eu₂O₃, Pr₂O₃, Dy₂O₃, and Y₂O₃) and high-entropy oxide (GdLaEuPrDyY)₂O₃ additives on the structural, mechanical, and radiation shielding properties of copper matrix composites were investigated. XRD and SEM-EDS analyses showed that the high-entropy oxide successfully formed in a single-phase bixbyite structure after mechanical alloying and was homogeneously distributed within the copper matrix. The rare earth oxide additive significantly reduced the crystal grain size of the Cu matrix and improved its mechanical properties. Specifically, the microhardness value reached 68.3 Hv in the composite with 20% high-entropy oxide additive, representing an increase of approximately 111% compared to pure copper (32.3 Hv). Gamma shielding results showed that the rare earth oxide additive significantly increased the photon attenuation capacity. Specifically, at 242 keV energy, the Dy₂O₃ additive increased the MAC value from 0.141 cm²/g to 0.246 cm²/g, providing a 74.5% improvement. The most important result is that the composite with 20% high-entropy oxide additive showed the highest shielding performance, achieving a MAC value of 0.278 cm²/g, which is significantly superior to pure copper. Furthermore, this composite exhibited the lowest HVL and MFP values, demonstrating the highest photon shielding efficiency. Neutron shielding analyses revealed that Gd₂O₃ and high-entropy oxide additives, in particular, increased thermal neutron attenuation performance to approximately 100%. These results demonstrate that high-entropy oxide additives provide a stronger impact compared to single oxide additives, offering superior performance in both gamma and neutron shielding. Consequently, copper composites doped with (GdLaEuPrDyY)₂O₃ stand out as promising alternative shielding materials for nuclear facilities, radiation protection systems, and advanced engineering applications due to their high shielding efficiency, improved mechanical properties, and non-toxic composition.

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