Yazarlar
- Karaduman, Oktay(8)
- Özkul, İskender(7)
- Canbay, Canan Aksu(6)
- ALMisned, Ghada(2)
- Aksu Canbay, Canan(2)
- Başbağ, Güneş(2)
- Güler, Ömer(2)
- Tekin, H.O.(2)
- Baykal, Duygu Sen(1)
- Boyrazli, Mustafa(1)
- Boyrazlı, Mustafa(1)
- Dehghanpour, Heydar(1)
- Doğan, Fatih(1)
- Güler, Seval Hale(1)
- Kalay, Ece(1)
- Kilic, G.(1)
- Kızılgün, Yasin(1)
- Yüzüak, Ercüment(1)
- Yüzüak, Gizem Durak(1)
- Çelik, Emrah(1)
- Şimşek, Telem(1)
- Şimşek, Tuncay(1)
Yayınlar
- MakaleYalnız künye2026Scopus SJRQ2Oxide Dispersion, Microstructure, and Functional Evolution in La2O3 Modified Cu-Al-Mn-Fe Shape Memory Alloys
Karaduman, Oktay; Doğan, Fatih; Dehghanpour, Heydar; Yüzüak, Gizem Durak; Yüzüak, Ercüment; Canbay, Canan Aksu
Cu-Al-Mn-Fe high-temperature shape memory alloys containing 0-1.0 wt.% La2O3 were fabricated by vacuum arc remelting to investigate oxide-dispersion effects on microstructure, martensitic transformation, wear, and corrosion behavior. XRD and SEM analyses revealed that low La2O3 additions (0.2-0.4 wt.%) promoted β1′ martensite refinement and enhanced crystallinity, while higher contents induced structural heterogeneity. The alloy with 0.4 wt.% La2O3 exhibited the highest transformation enthalpy (7.49 J g−1), reduced friction coefficient (~0.55), and the narrowest wear scar (~501 µm). Electrochemical tests in 3.5 wt.% NaCl showed a fivefold decrease in corrosion current density and increased charge-transfer resistance (2512 Ω cm2) for the same composition. Excessive La2O3 led to performance degradation due to particle agglomeration and interfacial defects. The results demonstrated that controlled La2O3 addition enabled microstructural refinement and multifunctional performance enhancement in Cu-based shape memory alloys.
- MakaleAçık Erişim2025Scopus SJRQ2Designing multifunctional ferromagnetic high-entropy shape memory alloys (FHESMAs): Cr and Mn influence on structural, physical, magnetic and nuclear radiation shielding in NiFeGaCo alloys
Özkul, İskender; Karaduman, Oktay; Şimşek, Tuncay; Şimşek, Telem; Canbay, Canan Aksu; Güler, Ömer; ALMisned, Ghada; Tekin, H.O.
This study systematically investigates the influence of Cr and Mn additions on the structural, magnetic, and radiation shielding properties of NiFeGaCo-based ferromagnetic high-entropy shape memory alloys (FHESMAs) synthesized via the arc melting method. The fabricated NiFeGaCo, NiFeGaCoCr, and NiFeGaCoMn alloys were comprehensively characterized in terms of their phase formation, microstructure, martensitic transformation behavior, and magnetic performance. The results demonstrated that Mn addition significantly improved the magnetic properties, yielding the highest saturation magnetization (56.64 emu/g) and lowest coercivity (5.55 Oe), making NiFeGaCoMn highly suitable for soft magnetic applications. In contrast, Cr addition provided moderate magnetic behavior but enhanced structural stability with the largest crystallite size and lowest lattice strain. Moreover, gamma-ray and fast neutron shielding investigations revealed that the Cr-containing alloy exhibited superior performance in terms of linear attenuation coefficient, half-value layer, effective electron density, and fast neutron removal cross-section values, while Mn addition slightly reduced these shielding capabilities. It can be concluded that Cr addition offers a balanced advantage in designing FHESMAs with combined magnetic sensitivity and radiation shielding efficiency, whereas Mn addition is more effective for maximizing magnetic performance with a compromise in shielding characteristics.
AtıfScopus2OpenAlex2
İncele - MakaleYalnız künye2025Scopus SJRQ2Effects of Trace Rare Earth (TRE) additions on thermal, crystal structure, and radiation shielding properties of CuAlMn high-temperature S-M alloys: A closer look at Cerium effect
Kalay, Ece; Özkul, İskender; Karaduman, Oktay; Kızılgün, Yasin; Güler, Ömer; Canbay, Canan Aksu; Kilic, G.; Baykal, Duygu Sen; ALMisned, Ghada; Tekin, H.O.
This study systematically investigates the effect of Ce addition on the thermal, structural, and radiation shielding properties of CuAlMn-based high-temperature shape memory alloys (HTSMAs). Among the different compositions, Ce-III demonstrated the most balanced performance, exhibiting optimized phase transformation behavior, microstructural refinement, and enhanced gamma-ray attenuation. Differential Scanning Calorimetry (DSC) analysis revealed that Ce-III exhibited lower transformation temperatures, with austenite start (As) and finish (Af) temperatures of 378.13 °C and 429.75 °C, respectively, and martensite start (Ms) and finish (Mf) temperatures of 402.52 °C and 341.91 °C, suggesting improved thermal stability. Microstructural analysis indicated significant grain refinement, attributed to Ce's dislocation pinning effect, which contributed to enhanced strength and radiation attenuation. X-ray diffraction (XRD) patterns confirmed the formation of Ce-rich intermetallic phases, such as Mn1.15Cu3.85Ce and Cu8Ce4, which increased density and photon interaction probability. The Ce-III alloy exhibited superior linear attenuation coefficients and reduced half-value layer, reinforcing its effectiveness as a radiation shielding material. It can be concluded that Ce-III represents an optimal composition with a synergistic combination of structural stability, phase transformation control, and enhanced radiation shielding capabilities, making it a promising candidate for nuclear and high-radiation applications.
AtıfOpenAlex1İncele - MakaleAçık Erişim2024Scopus SJRQ2Effects of Ga, Nb, V, Zr, and Cr on the crystal structures and thermal behavior of CuAlMn shape memory alloys
Özkul, İskender; Karaduman, Oktay; Canbay, Canan Aksu
CuAlMn alloys are cheaper and more promising alloy types compared to NiTi alloys. In this study, based on CuAlMn shape memory alloy, thermodynamic and structural characteristics of some new alloys containing four elements were investigated in detail. In this study, five new quaternary shape memory alloys, each containing a CuAlMn base alloy and a different fourth additive element (Ga, Nb, V, Zr, and Cr), were produced. The properties of the obtained alloys were characterized using a series of analysis methods such as X-ray diffraction (XRD), optical microscopy, differential scanning calorimetry (DSC), and differential thermal analysis (DTA). The results showed the effects of different elements on the crystal structures of the alloys and how different elements could change the thermal behavior of the alloys.
AtıfScopus4WoS3OpenAlex6İncele - MakaleAçık Erişim2024Scopus SJRQ2Hysteresis gap-shrinking and structural effects of minor Al and Ti modifications on binary CuAl-based high-temperature shape memory alloys
Karaduman, Oktay; Özkul, İskender; Aksu Canbay, Canan
Cu-based shape memory alloys (SMAs), except for exhibiting shape recovery, superelasticity, and high damping, are desirable because these smart materials have higher electrical and thermal conductivity and much lower prices than NiTi SMAs. However, they also have some downsides in mechanical strength and brittleness (mostly stemming from their coarse grain structure) and thermal instability. Therefore, adding some grain refining elements to these SMAs to improve their shape memory effect (SME), and thermal, structural, and mechanical properties is a widespread and simple way that significantly affects their martensitic phase transitions, structure, and mechanical properties. One of these grain-refining elements is titanium. Its thermal conductivity is lower than those of Cu and Al elements and has a low solubility in Cu-matrix. Besides the effects of small Al variations, the use of minor amounts of titanium in binary CuAl-base alloys can show impressive effects on all characteristics of these shape memory alloys, such as shape memory effect properties, martensitic transformation kinetics parameters, and microstructural features. In this research work, CuAlTi ternary high-temperature shape memory alloys (HTSMAs) with new compositions were produced by the arc melting method without a complicating use of Mn or Ni components in usual ternary CuAlMn and CuAlNi shape memory alloys. Thermal analyses of the prepared samples of the alloys were investigated by using differential scanning calorimetry (DSC) and differential thermal analysis (DTA) measurements. In contrast, x-ray diffraction (XRD) test results and optical micrographs were used for analyzing the structure of the alloy samples. The effect of different amounts of low soluble and grain refining Ti element on the binary CuAl alloy system was investigated.
AtıfScopus2WoS2OpenAlex2İncele - MakaleAçık Erişim2024Scopus SJRQ2High thermal stability effect of vanadium on the binary CuAl base alloy for a novel CuAlV high-temperature shape memory alloy
Karaduman, Oktay; Özkul, İskender; Güler, Seval Hale; Aksu Canbay, Canan
In this study, two high-temperature shape memory alloys (HTSMAs) of CuAlV with unprecedented chemical compositions were fabricated using the arc melting technique, followed by traditional ice-brine water quenching after the melting process. To characterize the shape memory properties and structure of the alloys, a series of tests including differential calorimetry (DSC and DTA), EDS, optical microscopy, and XRD were conducted. The DSC tests, performed at different heating and cooling rates, demonstrated highly stable reversible martensitic phase transformation peaks at high temperatures, which were also confirmed by the results of DTA tests. Microstructural XRD and optical microscopy tests were conducted at room temperature, revealing the martensitic structure of the alloys in both cases. Based on all the results, the effects of different minor amounts of vanadium additives directly on the CuAlV alloy were discussed.
AtıfScopus2WoS2OpenAlex3İncele - MakaleAçık Erişim2024Scopus SJRQ2Fabrication of CuAlVMg High-Temperature Shape Memory Alloy Containing Low-Soluble Vanadium Addition
Karaduman, Oktay; Boyrazli, Mustafa; Canbay, Canan Aksu; Özkul, İskender; Çelik, Emrah; Başbağ, Güneş
For the first time, CuAlVMg high-temperature shape memory alloy (HTSMA) with unprecedented alloy composition and with extended solubility of vanadium element was fabricated as-cast ingot by arc melting method, then homogenization of the alloy in high β-phase temperature region and quenching in iced-brine water were performed, respectively. The characteristic forward martensite to austenite martensitic transformation (MT) temperatures were detected at around 390 °C, which put the novel alloy in the category of HTSMAs. The thermal response of the alloy at high-temperatures was observed by DTA test as coherent with usual Cu-based HTSMAs. The residual sub-eutectoid precipitations emerging at around 500 °C hindered the direct martensitic transformation. The martensite structure of the alloy was revealed by XRD, SEM and optical microscopy tests.
- MakaleAçık Erişim2023Scopus SJRQ3Effect of 5.31Ti (at.%) content used as ternary in quaternary Cu-rich high-temperature shape memory alloy cast via arc melting
Başbağ, Güneş; Karaduman, Oktay; Canbay, Canan Aksu; Özkul, İskender; Boyrazlı, Mustafa
In this work, the new quaternary CuAlTiMg high-temperature shape memory alloy (HTSMA) with an unprecedented composition and with extended solubility of Ti was produced by the arc melting method. The thermal shape memory effect characterization tests were done by performing a series of differential calorimetric (DSC and DTA) measurements. The obtained thermograms of the alloy displayed the martensitic phase transformation peaks. The forward (martensite to austenite) phase transformation was found to occur at above 350◦C, which qualifies the produced alloy as an HTSMA. The microstructural XRD measurement was performed to reveal the atomic planes of martensite structures formed in the alloy, which constitute the shape memory effect property of the fabricated alloy. The alloy surface was monitored by optical microscopy image taken at room temperature, and finely dispersed Ti-rich X-phases were observed.