Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Güler, Ömer(7)
- Tekin, H.O.(5)
- Şimşek, Telem(4)
- Guler, Omer(3)
- Şimşek, Tuncay(3)
- ALMisned, Ghada(2)
- Alkarrani, Hessa(2)
- Almisned, Ghada(2)
- Avar, Barış(2)
- Baykal, Duygu Sen(2)
- Chattopadhyay, Arun K.(2)
- Güler, Seval Hale(2)
- Kilic, G.(2)
- Mesbahi, A.(2)
- Özkul, İskender(2)
- AlMisned, Ghada(1)
- Aslan, Naim(1)
- Bahceci, Ersin(1)
- Basgoz Orhan, Oykum(1)
- Başgöz, Öyküm(1)
- Boyrazlı, Mustafa(1)
- Canbay, Canan Aksu(1)
- Erdem, Emre(1)
- Evin, Ertan(1)
- Gul, Ali Oktay(1)
- Guler, Seval Hale(1)
- Güngör, Ahmet(1)
- Issa, Bashar(1)
- Kavaz, E.(1)
- Kavaz, Esra(1)
- Kumruoglu, Levent Cenk(1)
- Ozkul, Iskender(1)
- Sen Baykal, Duygu(1)
- Simsek, Tuncay(1)
- Yakin, Alican(1)
- Yayla, Nihal(1)
- Zakaly, Hesham M.H.(1)
- Özcan, Sadan(1)
Yayınlar
- MakaleAçık Erişim2026Scopus SJRQ2Designing a novel FeCoNiMnCu high-entropy Alloy: Synthesis, structural evolution, magnetic behavior, and radiation shielding performance
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.
AtıfScopus10OpenAlex6
İncele - MakaleAçık Erişim2025Scopus SJRQ2Effect of neodymium addition on the structural, mechanical, and magnetic properties of FeCoNiCu(MnCr)0.5 high entropy alloys
Yayla, Nihal; Şimşek, Telem; Boyrazlı, Mustafa; Güler, Ömer
Neodymium (Nd), a rare earth element, was incorporated into the [FeCoNiCu(MnCr)0.5] high-entropy alloy (HEA) at weight percentages of 0.5%, 1%, 2%, and 5%. The alloys were synthesized successfully using the arc melting method. X-ray diffraction (XRD) analysis confirmed that both the undoped and Nd-doped alloys exhibit a single-phase solid solution with a face-centered cubic (FCC) crystal structure, consistent with thermodynamic predictions derived from the Miedema model. Scanning electron microscopy (SEM) revealed a dendritic structure in the undoped alloy, which was replaced by Cu- and Cr-rich regions in the 5% Nd-doped alloy, as confirmed by energy dispersive spectroscopy (EDS). Differential scanning calorimetry (DSC) indicated an endothermic peak in the undoped alloy and minor thermal responses in Nd-doped samples, without distinct phase transitions within the 0–800 °C range. Mechanical testing demonstrated substantial enhancements in both hardness and tensile strength with increasing Nd content. The 5% Nd-doped alloy exhibited the highest performance, achieving a Vickers hardness of 370 HV and a tensile strength of 1186 MPa. Magnetic testing indicated ferromagnetic behavior in all samples, with Nd additions significantly enhancing magnetic properties. Notably, the 5% Nd-doped alloy achieved a saturation magnetization (Ms) of 41 emu/g and a coercivity (Hc) of 6.3 Oe, highlighting improved magnetic softness and rapid magnetization loss characteristic of soft magnetic materials.
AtıfScopus2WoS1OpenAlex1İncele - Derleme MakaleYalnız künye2025Scopus SJRQ2A critical review of the refractory high-entropy materials: RHEA alloys, composites, ceramics, additively manufactured RHEA alloys
Guler, Seval Hale; Yakin, Alican; Guler, Omer; Chattopadhyay, Arun K.; Simsek, Tuncay
In this study, the traits, production methods, and applications of refractory high-entropy materials—including refractory high-entropy alloys (RHEAs), refractory high-entropy composites (RHE-Cs), and refractory high-entropy ceramics (RHE-Ce)—which are part of the broader category of refractory high-entropy materials with a wide range of applications, have been thoroughly examined and discussed. RHEAs have emerged as materials that exhibit superior properties, such as high melting temperatures, excellent temperature resistance, and high wear and corrosion resilience, in addition to high mechanical and fatigue strength. These attributes have made them extensively studied materials in recent times. The properties of RHEAs suggest their safe operation in challenging environments such as nuclear reactors, gas turbines, aerospace, and energy production. Among refractory materials, RHE-Cs stand out for their high strength and low density, showing significant potential for use in the automotive, aerospace, and space industries. Another group with a wide range of applications, RHE-Ce materials, is distinguished by their high-temperature resilience, high hardness, and low thermal conductivity, making them suitable for high-temperature environments. Refractory materials are generally fabricated using traditional techniques such as arc melting, powder metallurgy, and magnetron sputtering. In this study, along with traditional production methods, additive manufacturing techniques which have revolutionized the manufacturing field are discussed concerning their applications in refractory material production. Additive manufacturing methods enable the achievement of high temperatures and the production of homogeneous, single-phase solid solutions, making them suitable for fabricating refractory materials with high melting points.
AtıfScopus37WoS35OpenAlex41İncele - MakaleYalnız künye2025Scopus SJRQ2Phase Stability, Structural Properties, Electronegativity, Mechanical Properties, and Neutron and Gamma-Ray Attenuation Properties of Cantor High Entropy Alloys for Advanced Nuclear Applications
Tekin, H.O.; Güler, Ömer; Özkul, İskender; AlMisned, Ghada; Baykal, Duygu Sen; Alkarrani, Hessa; Kilic, G.; Mesbahi, A.
High Entropy Alloys (HEAs) hold considerable potential for sophisticated nuclear applications, offering a vast spectrum of compositional tuning to enhance mechanical properties at high temperatures, as well as to increase resistance to radiation and corrosion. This study explores the suitability of Cantor HEAs, specifically the CoCrFeMnNi matrix enriched with elements such as Zr, Nb, Mo, Hf, Ta, and W, for nuclear applications. These elements were selected for their high atomic numbers and neutron capture cross-sections, vital for enhancing gamma-ray and neutron shielding properties. Utilizing advanced computational and theoretical methods, the elastic modulus of these alloys was theoretically estimated while their radiation attenuation capabilities were evaluated through different Monte Carlo simulation codes. CoCrFeMnNiW demonstrated the highest elastic modulus (340.9 GPa), indicating significant mechanical robustness. The addition of W resulted in superior gamma-ray attenuation, with the lowest gamma-ray transmission factors and highest neutron shielding effectiveness among the studied alloys. The calculated mass attenuation coefficients and effective removal cross-sections values demonstrate the potential of these HEAs to provide effective radiation shielding. Our results showed a clear correlation between the elastic modulus and radiation attenuation properties, suggesting that mechanical stiffness does not compromise shielding capabilities. The comprehensive analysis of thermodynamic and structural parameters, including entropy of mixing, mixing enthalpy, and Valence Electron Concentration (VEC), provided essential insights into phase stability and microstructural characteristics. It can be concluded that CoCrFeMnNiW and its related Cantor HEAs as promising materials for advancing nuclear technology, offering a new horizon for safer and more efficient nuclear systems.
AtıfScopus9OpenAlex13İncele - MakaleAçık Erişim2025Scopus SJRQ1High-Entropy Alloys and Oxides as Supercapacitor Electrodes: A Structural and Electrochemical Perspective for Energy Storage
Başgöz, Öyküm; Güngör, Ahmet; Güler, Ömer; Erdem, Emre
This study investigates the performance of high entropy alloys [Fe3Cr3Mn2NiV, HEA)] and high entropy oxides [(Fe3Cr3Mn2NiV)O4, HEO)] as electrode materials for supercapacitors. HEA is synthesized through mechanical alloying, followed by HEO forming via an oxidation process. XRD results demonstrate HEA comprises both amorphous and crystalline phases, whereas HEO has an entirely crystalline structure. SEM analyses showed HEA exhibits larger and irregular particles, whereas HEO displays a smaller and spherical morphology. EPR analyses revealed significant changes in defect structures and unpaired electron configurations during the transition from HEA to HEO. HEA is prone to diffusion-controlled processes due to their regular structure and strong magnetic interactions; however, HEO exhibits capacitive behavior based on surface redox reactions and pseudo-capacitive mechanisms due to their irregular structure and oxygen vacancies. CV analyses revealed that HEO contributes more capacitive via surface redox reactions, while GCPL results suggested that HEO demonstrated superior energy density (40.8 Wh kg−1) and power density (14.3 kW kg−1). Impedance analyses revealed that HEO exhibited reduced internal resistance and enhanced ion conductivity, whereas HEA demonstrated higher resistance and diffusion-controlled processes. In conclusion, HEA and HEO exhibit distinct energy storage mechanisms, and these materials can be optimized for supercapacitor applications.
AtıfScopus36WoS34OpenAlex18İncele - MakaleAçık Erişim2025Scopus SJRQ2Effect of Tungsten Content on the Microstructure, Mechanical and Tribological Properties of AlCoCrFeNi High-Entropy Alloys
Bahceci, Ersin; Gul, Ali Oktay; Basgoz Orhan, Oykum; Kumruoglu, Levent Cenk; Guler, Omer
High-entropy alloys (HEAs) have recently attracted considerable attention due to their unique combination of high strength, hardness, and corrosion and wear resistance, making them promising candidates for advanced structural and functional applications. Among these, AlCoCrFeNi-based HEAs are well known for their high hardness and good wear resistance; however, their limited tribological stability under operational conditions restricts their broader application. To address this limitation, tungsten (W) was incorporated into the AlCoCrFeNi system to enhance its mechanical and tribological performance. In this study, the microstructural, mechanical, and tribological properties of AlCoCrFeNiWx (x = 0, 0.1, 0.25, 0.5 and 1 mol) HEAs were systematically investigated. The alloys were fabricated using the vacuum arc melting method and characterized by XRD, SEM-EDS, elemental mapping, microhardness, and wear tests. The addition of W caused a shift in the 2θ ≈ 44° (110) peak toward lower angles. While the W-free alloy exhibited Body-Centered Cubic (BCC) + B2 phases, W addition led to the formation of a new W-rich phase, and at higher W contents, a pure W phase appeared. The hardness increased from 507.11 HV1 to 651.81 HV1 with increasing W content. Furthermore, wear resistance improved and the coefficient of friction decreased with higher W addition. When comparing the W-free alloy to the alloy with the highest W content, the wear rate decreased by approximately 1.85 times under a 2 N load and 1.89 times under a 5 N load. These results demonstrate that W addition significantly enhances the wear resistance of AlCoCrFeNi-based HEAs by nearly twofold.
AtıfScopus1WoS1OpenAlex1İncele - MakaleYalnız künye2024Scopus SJRQ2Exploring thermodynamic, physical and radiative interaction properties of quinary FeNiCoCr high entropy alloys (HEAs): a multi-directional characterization study
ALMisned, Ghada; Guler, Omer; Ozkul, Iskender; Sen Baykal, Duygu; Alkarrani, Hessa; Kilic, G.; Mesbahi, A.; Tekin, H.O.
To qualify for nuclear applications, materials must meet specific criteria, including mechanical properties, high-temperature behavior, corrosion resistance, and high-temperature oxidation resistance. High Entropy Alloys (HEAs) are particularly suitable for these applications due to their unique properties. Consequently, we conducted a theoretical and simulation-based approaches to assess some critical properties including radiation shielding properties of some quinary FeNiCoCr HEAs. In this study, we focused on quinary FeNiCoCr HEAs, whose corrosion properties have been previously examined in the literature. We investigated the thermodynamic and radiation shielding properties of HEAs with sixteen different compositions. Our methodology included evaluating thermodynamic parameters such as Mixing Entropy (∆Smix) and Mixing Enthalpy (∆Hmix), as well as structural characteristics like Valence Electron Concentration (VEC) and Atomic Size Difference (δ). This allowed us to systematically deduce the phase behavior and stability of various HEAs. Through computational modeling, we assessed the radiation shielding capabilities of these alloys, particularly their effectiveness in attenuating gamma ray and fast neutrons. The results identified FeNiCoCrW as the alloy with the lowest fast neutron removal cross-section values, highlighting its potential for nuclear applications. Its high melting point and the synergistic interplay between its elemental composition and thermodynamic properties suggest broad applicability in extreme environments. Thus, FeNiCoCrW emerges as a promising HEA with multifunctional capabilities, warranting further exploration and potential integration into advanced engineering solutions.
AtıfScopus8OpenAlex10İncele - MakaleYalnız künye2024Scopus SJRQ2Exploring critical behavioral differences in physical, structural, and nuclear radiation attenuation properties of produced High Entropy Alloy (HEA) and Refractory-High Entropy Alloy (RHEA) samples
Güler, Seval Hale; Güler, Ömer; 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.
AtıfScopus26OpenAlex29İncele - MakaleAçık Erişim2023Scopus SJRQ1FeCoNiMnCr high-entropy alloys (HEAs): Synthesis, structural, magnetic and nuclear radiation absorption properties
Şimşek, Telem; Kavaz, Esra; Güler, Ömer; Şimşek, Tuncay; Avar, Barış; Aslan, Naim; Almisned, Ghada; Zakaly, Hesham M.H.; Tekin, H.O.
We report the synthesis and structural, magnetic and Radiation shielding properties of High Entropy Alloy (HEA) produced through mechanical alloying method. Using an X-Ray Diffractometer (PanalyticalEmpryan) with CuK radiation at 45 kV and 40 mA, the phase identification starting elements and as-milled powders are identified. Scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDX), morphological and microstructural investigations were conducted (FEI Quanta FEG 450). EDX and elemental mapping analyses are conducted to assess the purity and elemental distributions of the synthesized alloys. Using the Quantum Design Physical Characteristics Measurement System (PPMS) with vibrating sample magnetometer (VSM) and a magnetic field of 30 kOe at room temperature, magnetic properties are examined. Using 137Cs radioisotope and mathematical methods, gamma-ray and neutron shielding properties of HEA are investigated in a conventional transmission setup using experimental and theoretical approaches. In the presence of a 3 T applied field, the sample exhibits a low magnetization of 5.30 emu/g at 300 K. Moreover, Ms is raised to 22 emu/g at 10 K owing to decreased thermal effects. The temperature dependence of the magnetization is recorded in the presence of a 1 T applied field. HEA exhibits superior neutron attenuation properties than conventional absorption materials such as B4C, graphite, and water. Our results showed that the synthesized HEA has superiority over other alloys and conventional neutron absorption materials. It can be concluded that the proposed novel HEA might be investigated further in terms of broadening its characterization and clarifying its other crucial properties to extend the scope of the current investigation.
AtıfScopus42OpenAlex47İncele - MakaleAçık Erişim2022Scopus SJRQ2Effect of Cu, Sn and Sb addition on the structural, thermal and magnetic properties of body-centered cubic structured CoNiMnGaSi high entropy alloy
Şimşek, Telem; Özkul, İskender; Canbay, Canan Aksu; Avar, Barış; Şimşek, Tuncay; Güler, Seval Hale; Özcan, Sadan; Güler, Ömer; Chattopadhyay, Arun K.
In this study structural, morphological, thermal and magnetic properties of equiatomic CoNiMnGaSi (base), CoNiMnGaSiCu, CoNiMnGaSiSn and CoNiMnGaSiSb alloys are discussed. The formation of solid-solution nanocrystalline bcc structure of the alloys was determined by XRD and DTA techniques. SEM–EDS analyses also revealed the homogeneous distribution of the elements. The room temperature magnetic hysteresis loops showed that as-casted alloys reached saturation easily with coercivity less than or equal to 35 Oe. As the Cu and Sn were added to the alloy, the saturation magnetization was decreased from 112 emu/g to 50 emu/g, which was mainly due to the substitution of non-magnetic atoms to the magnetic Co in the base CoNiMnGaSi alloy, whereas the addition of Sb to the base alloy did not have a significant effect on the Ms. The CoNiMnGaSiSb was found to have the highest Curie Temperature of 670 K, which makes the alloy a promising candidate for power industry-related applications.
AtıfScopus3OpenAlex4İncele