Yazarlar
- Karaduman, Oktay(4)
- Özkul, İskender(4)
- Aksu Canbay, Canan(2)
- Canbay, Canan Aksu(2)
- ALMisned, Ghada(1)
- Balci, Esra(1)
- Başbağ, Güneş(1)
- Boyrazli, Mustafa(1)
- Güler, Seval Hale(1)
- Güler, Ömer(1)
- Kanca, M Sait(1)
- Kök, Mediha(1)
- Qader, Ibrahim Nazem(1)
- Tatar, Cengiz(1)
- Tekin, H.O.(1)
- Çelik, Emrah(1)
- Şan, Mert Hüseyin(1)
- Şimşek, Telem(1)
- Şimşek, Tuncay(1)
Yayınlar
- MakaleAçık Erişim2026Scopus SJRQ2Pressure-induced transformation in NiTi-CuAg shape memory alloys: investigation of microstructural and thermodynamic changes
Tatar, Cengiz; Kök, Mediha; Kanca, M Sait; Balci, Esra; Qader, Ibrahim Nazem
Shape memory alloys (SMAs), particularly nickel-titanium (NiTi) based systems, are widely recognized for their unique shape memory effect and superelastic behavior, driven by reversible martensitic phase transformations. To enhance these functional properties for advanced applications, alloying with elements such as copper (Cu) and silver (Ag) has been explored. This study investigates the synthesis and characterization of a novel quaternary NiTiCuAg shape memory alloy. The alloy was fabricated via arc-melting from high-purity elemental powders, followed by application of varying uniaxial compressive pressures to assess their effects on phase transformation behavior. Thermal, structural, and microstructural properties were evaluated using Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy coupled with Energy-Dispersive x-ray Spectroscopy (SEM-EDX), and x-ray Diffraction (XRD). The results aim to elucidate the combined effects of compositional tailoring and mechanical processing on the functional performance of NiTiCuAg SMAs, with implications for their use in high-performance, pressure-sensitive applications.
- MakaleAçık Erişim2025Scopus SJRQ2Comprehensive evaluation of thermal, structural, magnetic, and radiation shielding properties of CuAlNi and CuAlNi-X (X = Co, CoFe, CoFeMn, CoFeMnCr) high-temperature shape memory alloys
Özkul, İskender; Karaduman, Oktay; Şimşek, Telem; Şimşek, Tuncay; Canbay, Canan Aksu; Güler, Ömer; Şan, Mert Hüseyin; ALMisned, Ghada; Tekin, H.O.
This study investigates the thermal, structural, magnetic, and radiation shielding properties of CuAlNi-based high-temperature shape memory alloys (HTSMAs) enhanced through sequential alloying with Co, Fe, Mn, and Cr. Five different variants were produced, designated as CRef (reference CuAlNi alloy), CCo (CuAlNiCo), CFe (CuAlNiCoFe), CMn (CuAlNiCoFeMn), and CCr (CuAlNiCoFeMnCr). Differential scanning calorimetry (DSC) confirmed the presence of reversible martensitic transformations in all alloys, with Co and Mn additions significantly enhancing thermal stability. Structural analyses using X-ray diffraction (XRD) and microscopy showed significant grain refinement and phase transitions, while magnetic measurements highlighted the strong ferromagnetic response of CCo (CuAlNiCo) and the increased coercivity of CMn (CuAlNiCoFeMn) due to domain-pinning effects. Moreover, radiation shielding analyses demonstrated the critical influence of density and elemental composition, with CRef exhibiting superior linear attenuation coefficients (LAC), effective atomic number (Zeff), and energy absorption buildup factor (EBF) performance, attributed to its optimized Cu fraction and high density (7.1296 g/cm3). In contrast, CMn (CuAlNiCoFeMn) showed the weakest shielding properties due to reduced density and Mn content. Among the samples, CRef emerged as the superior alloy, demonstrating exceptional multifunctionality across all evaluated parameters, while CCr (CuAlNiCoFeMnCr) displayed synergistic properties, combining shape memory behavior with competitive shielding efficiency. It can be concluded that CuAlNi-based HTSMAs hold significant potential as multifunctional materials, particularly for nuclear safety and aerospace engineering applications, where adaptive functionality and radiation protection are critical.
AtıfScopus2OpenAlex2
İncele - 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.