Yazar "Guler, Seval Hale" seçeneğine göre listele

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    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
    (Elsevier Sci Ltd, 2024) Gunoglu, Kadir; Guler, Seval Hale; Guler, Omer; Almisned, Ghada; Ozkavak, Hatice Varol; Albayrak, M. Gokhan; Akkurt, Iskender
    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 (sigma R) 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.
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    Exploring critical behavioral differences in physical, structural, and nuclear radiation attenuation properties of produced High Entropy Alloy (HEA) and Refractory-High Entropy Alloy (RHEA) samples
    (Elsevier, 2024) Guler, Seval Hale; Guler, Omer; Kavaz, E.; Almisned, Ghada; Issa, Bashar; Tekin, H. O.
    Refractory-High entropy alloys (RHEAs) are known for their exceptional mechanical and radiation-resistant properties, making them promising materials for use in nuclear reactors. Their high entropy composition, which consists of multiple elements in roughly equal proportions, can create a stable microstructure that withstands high levels of radiation damage. The objective of this work is to further our comprehension of the unique behavioral, physical, structural, and nuclear radiation attenuation characteristics shown by High-Entropy Alloys (HEA) and Refractory-High entropy alloy (RHEA) materials. Accordingly, two high entropy alloy (HEA) samples through two different compositions were produced. The first composition under consideration is the typical high-entropy alloy (HEA) defined as MnCrFeNiCoMo0.5. The second composition under consideration is a refractory high entropy alloy (RHEA) characterized by the following elemental composition: TiZrNbHfVTa0.1. SEM and EDX analyses were conducted in terms of determining their physical and structural attributes. Next, a133Ba radioisotope together with a HPGe detector were utilized for gamma-ray transmission experiments. Finally, a241Am/Be source and a gas proportional detector were used for neutron absorption experiments for HEA and RHEA samples. The alloy structures displayed a unique degree of uniformity. Throughout the RHEA phase, the incorporation of refractory elements did not provide any discernible adverse impacts on the physical stability. The counting spectrum provided a clear explanation of the gamma ray absorption features shown by the RHEA (R) sample, highlighting its exceptional absorption properties. Regarding the absorption properties of neutrons, it was observed that RHEA had a comparatively reduced amount of absorption. Therefore, it can be concluded that the basic structure of RHEA grants it superior gamma-ray attenuation qualities compared to HEA. It can be concluded that RHEA demonstrates superior applicability as a material in comparison to HEA, especially in situations involving the use of fuel rods, where maintaining of neutron quantity has paramount importance for achieving optimum neutron activation.
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    Fabrication and structural, physical, and nuclear radiation shielding properties for Oxide Dispersion-Strengthened (ODS) alloys through Erbium (III) oxide, Samarium (III) oxide, and Praseodymium (III) oxide into 316L matrix
    (Elsevier Sci Ltd, 2024) Guler, Seval Hale; Guler, Omer; Kavaz, E.; Almisned, Ghada; Albayrak, M. Gokhan; Issa, Bashar; Tekin, H. O.
    We report a comprehensive investigation on customization process of Oxide Dispersion-Strengthened alloys through Sm2O3, Pr2O3, and Er2O3 incorporation into 316L stainless steel matrix in terms of a desired enhancement in structural, physical, and nuclear radiation shielding properties. Oxide powders are incorporated into 316L stainless steel powder all with the same purity of 99.5%. These were Erbium oxide (Er2O3), Praseodymium oxide (Pr2O3), and Samarium oxide (Sm2O3). First, X-Ray diffraction and Scanning Electron Microscope/Energy-dispersive X-ray spectroscopy analyses are conducted in order to investigate their physical and structural properties. Next, two different experimental setups are employed using a133Ba and 241Am/Be sources for the measurements of gamma-ray and neutron transmission properties of Oxide Dispersion -Strengthened alloys. The maximum density increment is achieved through Er2O3 compared to other rein-forced oxides. The detector counting value reached its minimum level when a 5% Er2O3 oxide dispersion was introduced into the 316L SS matrix. Similarly, the most significant degree of photon absorption, the highest values of mass attenuation coefficient, lowest half value layer, and most effective atomic number, were all attained by the same sample. Based on the findings derived from the investigation, it can be concluded that incorporating Er2O3 oxide into 316L steel can be considered as a viable option in terms of enhancing the critical properties of Oxide Dispersion-Strengthened alloys for extreme conditions such as nuclear reactors and other similar fields, where the behavioral attributes of the utilized materials are at utmost importance.
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    Graphene nanoplatelet-reinforced high entropy alloys (HEAs) through B4C incorporation: structural, physical, mechanical, and nuclear shielding properties
    (Springer Heidelberg, 2023) Gul, Ali Oktay; Kavaz, Esra; Basgoz, Oykum; Guler, Omer; Almisned, Ghada; Bahceci, Ersin; Guler, Seval Hale
    This study aims to explicate the diverse roles of high entropy alloys within nuclear environments. The study extensively investigates the impact of B4C on the structural, physical, mechanical, and nuclear shielding properties of synthesized high-entropy alloys (HEAs) comprising FeNiCoCrW, GNP, and B4C. The aim is to explore the monotonic effects of B4C on the behavioural changes of the HEAs. The present study initially investigates the internal morphology and structural characteristics of the produced composites through the utilization of X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy. The determination of coefficient of friction values is obtained via wear testing, wherein the values are measured as a function of the sliding distance. The shielding properties of nuclear radiation are determined through the experimental setups for gamma-ray and neutron radiation. The sample encoded as G2, which incorporates both B4C and GNPs as reinforcing agents, exhibits the most noteworthy mechanical properties among the samples that were examined. The findings of our study indicate that augmenting the concentration of B4C has a significant impact on the efficacy of nuclear radiation shielding. The present study infers that the B4C produced within the framework of GNPs plays a significant role in enhancing the overall characteristics of HEAs. This is particularly noteworthy in the context of nuclear applications, where HEAs are being examined as a prospective constituent of forthcoming nuclear reactors. Moreover, B4C serves as a versatile instrument in scenarios, where there is a need to enhance mechanical and nuclear shielding properties across a spectrum of radiation energies.
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    Oxides dispersion-strengthened (ODS) FeCoNiCuZn high entropy alloys through different rare earth elements: Synthesis, structural, physical, and experimental radiation transmission properties
    (Elsevier Sci Ltd, 2023) Guler, Omer; Kavaz, E.; Guler, Seval Hale; Almisned, Ghada; Ozkul, Iskender; Basgoz, Oykum; Tekin, H. O.
    The oxide dispersoids within ODS alloys can act as sinks for radiation-induced defects, such as vacancies and dislocation loops, effectively reducing their mobility and preventing their accumulation. This property is crucial for HEAs employed in radiation-intensive environments, such as nuclear reactors. The objective of this research is to examine the impact of rare earth elements (REE) such as Y2O3, Er2O3, Pr2O3, and Sm2O3, on Oxides Dispersion-Strengthened (ODS) FeCoNiCuZn High Entropy Alloys (HEAs). The mechanical alloying technique is employed to produce a high entropy alloy consisting of Fe, Co, Ni, Cu, and Zn in their raw form. Subsequently, the raw alloy powder is enriched with separate amounts of Y2O3, Er2O3, Pr2O3, and Sm2O3. The microstructural analysis of the samples obtained from the mechanical alloying process was performed utilizing the X-ray diffraction (XRD) technique. In addition, scanning electron microscopy (SEM) was employed to analyze the ODSHEA samples encoded S1, S2, S3, S4, and S5. To investigate the transmission properties of gamma-ray and neutron radiation, experimental studies are carried out using two types of detectors: Ultra High Purity Germanium (HPGe) detector and Canberra NP-100B BF3 gas proportional detector, respectively. The X-ray diffraction (XRD) spectra of samples did not display any observable peaks that could be attributed to the presence of dispersed rare earth element (REE) oxides. The uniform distribution of the metallic constituents that make up the High Entropy Alloy (HEA) is observed in the samples. Additionally, it can be observed that the implementation of the ODS-HEA technique, incorporating a 3% (wt.) Er2O3 additive, results in the most advantageous results with respect to the characteristics of gamma ray absorption. The S3 sample demonstrated the greatest degree of neutron absorption, as demonstrated by a recorded value of 0.857 mu Sv/h, where the S1 sample demonstrated the minimum level of absorption, as evidenced by a recorded value of 0.452 mu Sv/h. Based on the observed effects on neutron and gamma-ray attenuation behaviors in ODS-HEAs, it can be concluded that Er2O3 exhibits characteristics of a monotonic oxide. This feature is particularly advantageous for applications that necessitate a dual enhancement in these behaviors. It can also be concluded that the S1 sample may be deemed appropriate for situations where the utmost consistency of chain reactions in nuclear reactor fuel rods is desired, due to its possession of the lowest neutron absorption properties.