Sürdürülebilir Kalkınma Amaçları

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• MakaleAçık Erişim2025/r/gumushane/13930
  Experimental determination of the compression behavior of RTV silicone rubber-based magnetorheological (MR) materials under static loading

  Mazlum, Ugur; Celik, Ilhan

  In this study, MR elastomer (MRE) materials were produced using seven different types of silicone rubber and five different types of magnetically sensitive ferromagnetic powders. The MRE materials were obtained in three states: pure, isotropic (homogeneous), and anisotropic (aligned). Compression tests were conducted using a uniaxial testing machine, with engineering stress–strain curves, tangent modulus, and MR-strain behavior graphs generated, considering powder ratio, powder type, and hardness values. The goal was to investigate the positive effects of magnetic field influence on these parameters and how the alignment state affected the stress performance of the materials. As a result, the highest stress increase at 10% strain was observed in materials containing 40% powder, with magnetic field comparison showing the most significant results. With the EM powder type at a 30% powder ratio in the isotropic state, a 563% increase in stress was obtained. Among the matrix materials with the same hardness, the most robust material was determined to be the MM240 TV with a Shore hardness of 40. Furthermore, the most significant increase in tangent modulus under the influence of the magnetic field was observed in vertically aligned materials. Compared to the pure material, a 3127% increase was found at 0.57% strain in vertically aligned samples. In materials with Shore hardness of 2, using Basf CN powder at 10–40% powder ratios, the highest relative MR effect was observed at a 20% powder ratio. The stress increase for vertically aligned samples compared to the pure state was 1274.6% at 0.27% strain. When comparing the relative MR effect of materials with Shore hardness between 10 and 59, the largest increase was obtained from the Sorta Clear matrix material.

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• MakaleYalnız künye2023/r/gumushane/12693
  Determination of shear behavior of magneto-rheological elastomers under harmonic loading

  Mazlum, Ugur; Celik, Ilhan

  Magneto-rheological (MR) materials can respond reversibly and quickly under the effect of an external magnetic field. MR materials contain micron-sized iron particles. These iron particles are typically dispersed in an elastomer or a liquid. These materials due to their properties constitute a kind of smart material in terms of engineering material. Such materials are used as isolators in various engineering applications, structures, and sound control subsystems. This study aimed to determine the mechanical properties for shear behavior of MR materials for under harmonic loading. Parameters such as matrix materials with different hardness values, powder types, magnetic field, frequency, and deformation were studied. The parameters related to the MR material itself were analyzed with the obtained data. The present study reveals that considering the sensitivity to magnetic field parameter, composite materials having the most suitable properties were produced with Shore 2 hardness value and SQ magnetic powder. It had been observed on increase about 200% at the rate of Shore A10 and A2 as a result of comparing the hardness scale. Also according to the powder rate while there was an increase on worth effect of relative MR, it is seen that the biggest increase had been in SQ powder with 199% worth. When looked some studies in literature, about comparing different hardness values such as matrix materials powder types etc. there aren’t any studies. The state of magnetic field thinks that features such as MR effect, Storage, and Loss modulus haven’t been examined yet.

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• MakaleAçık Erişim2019/r/gumushane/18246
  Investigation of Structural Properties and Wear Behavior of Surface Treated AZ31 Mg Alloy

  Çelik, İlhan

  Magnesium (Mg) and its alloys have a low density. For this reason, they are recognized as light metallic materials. Magnesium and its alloys have the potential capability to be widely used especially in the automotive, aviation and biomedical applications. However, their wear and corrosion resistance are very poor, so their area of usage is limited. This situation may adversely affect their usage without surface treatment despite their relatively well mechanical properties. Arc PVD technique was used to increase the wear resistance of AZ31 Mg alloy in this study. The surface coating process was applied to AZ31 Mg specimens as desired. Microstructural and morphological studies were done with XRD and SEM appliances. Pin-on-disc wear tests were performed to determine tribological properties. Through this study it was determined that AZ31 Mg alloy showed superior mechanical properties after applied CrN coating.

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• MakaleYalnız künye2019/r/gumushane/15016
  Production of silicone-based composite doped with waste NdFeB magnet and determination of mechanical properties by transforming experimental results into images

  Çelik, İlhan; Akben, Selahaddin Batuhan; Mazlum, Uğur

  Waste neodymium–iron–boron (NdFeB)-doped silicon-based magnetic polymer composites are obtained by mixing the double-doped mixtures with a 70–30% ratio. In this study, composite materials were produced by adding NdFeB magnetic particles with sizes between 0–45, 45–63, 63–125, and over 125 (µm), and compression experiments were carried out to determine the mechanical properties of them. Experimental results were transformed into images and then analysed using image processing methods. According to the analysis of images representing the results of compression experiments, the strength values of NdFeB–RTV (vulcanized at room temperature) silicone rubber have increased by increasing the magnetic powder ratio. In addition, it was observed that there is a decrease in the elongation at break values due to weakening of polymer chain bonds. Considering the sensitivity of the successfully produced composite materials to the magnetic field, significant improvements in strength values were obtained. It is hoped that these results will lead to an increase in the recycling rate of waste magnets and will prevent environmental damage.

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• MakaleYalnız künye2017/r/gumushane/15025
  Improving by postoxidation of corrosion resistance of plasma nitrocarburized AISI 316 stainless steels

  Yenilmez, A.; Karakan, M.; Çelik, I.

  Austenitic stainless steels are widely used in several industries such as chemistry, food, health and space due to their perfect corrosion resistance. However, in addition to corrosion resistance, the mechanic and tribological features such as wear resistance and friction are required to be good in the production and engineering of this type of machines, equipment and mechanic parts. In this study, ferritic (FNC) and austenitic (ANC) nitrocarburizing were applied on AISI 316 stainless steel specimens with perfect corrosion resistance in the plasma environment at the definite time (4 h) and constant gas mixture atmosphere. In order to recover corrosion resistance which was deteriorated after nitrocarburizing again, plasma postoxidation process (45 min) was applied. After the duplex treatment, the specimens’ structural analyses with XRD and SEM methods, corrosion analysis with polarization method and surface hardness with microhardness method were examined. At the end of the studies, AISI 316 surface hardness of stainless steel increased with nitrocarburizing process, but the corrosion resistance was deteriorated with FNC (570 °C) and ANC (670 °C) nitrocarburizing. With the following of the postoxidation treatment, it was detected that the corrosion resistance became better and it approached its value before the process.

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• MakaleAçık Erişim2017/r/gumushane/15010
  Influence of Duplex Treatment on Structural and Tribological Properties of Commercially Pure Titanium

  Çelik, Ilhan

  Titanium and its alloys are widely used in many fields, including aerospace and the chemical and biomedical industries. This is due to their mechanical properties, excellent corrosion resistance, and biocompatibility although they do have poor wear resistance. In this study, a duplex layer was successfully formed on the commercially pure titanium surface by duplex treatments (plasma nitriding and physical vapor deposition (PVD)). In the initial treatment, plasma nitriding was performed on the pure titanium samples and in the second treatment, the nitrided samples were coated with CrN by PVD. The friction and wear properties of the duplex-treated samples were investigated for tribological applications. Surface morphology and microstructure of the duplex-treated samples were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). In addition, the tribological properties were investigated using pin-on-disc tribometer. A compound layer composed of ϵ-Ti2N and δ-TiN phases and a diffusion layer formed under the compound layer were obtained on the surface of pure titanium after the nitriding treatments. CrN coated on the nitrided surface provided an increase in the surface hardness and in the wear resistance.

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• MakaleYalnız künye2017/r/gumushane/12959
  Selection application of material to be used in hip prosthesis production with analytic hierarchy process: Anwendungsselektion des zu verwendenden Materials in der Hüftprothesenproduktion mit dem analytischen Hierarchieverfahren

  Çelik, İ.; Eroğlu, H.

  Metallic biomaterials used in making hip prosthesis are required to meet expectations in terms of fatigue strength, corrosion resistance, wear resistance, cost and biocompatibility. It is also desirable that the modulus of elasticity they possess is close to the level of the possible bone. Metallic biomaterials face the problem of ion release even though they meet the criteria mentioned above. As a result, the choice of metallic material to be preferred in the manufacture of hip prosthesis can be made by evaluating all these criteria among themselves and by the performances of biomaterials to be compared according to these criteria. In this study, firstly the criteria expected from the metals to be used as biomaterials have been determined. Expert opinions about the subject and criteria determined in accordance with the studies in the literature by using analytical hierarchy process have been graded according to each other. Afterwards, selection of the most appropriate material was ensured by making the order of importance according to the criteria of the candidate materials.

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• MakaleYalnız künye2016/r/gumushane/18838
  Crn kaplanan saf titanyumun yapısal ve tribolojik özelliklerinin incelenmesi

  Çelik, İlhan

  Temas halinde çalışan makine elemanlarının bulunduğu uygulamalarda veya korozif ortamlarda kullanılan mühendislik malzemelerinin kullanım ömürlerini uzatmak için genellikle yüzey kaplama yöntemlerinden yararlanılmaktadır. Bu kaplama yöntemlerinin en önemlilerinden bir tanesi PVD kaplama işlemidir. PVD kaplama, birçok mühendislik uygulamalarında kullanılan makine elemanlarının yüzey özelliklerini iyileştirmek için yaygın bir şekilde kullanılmaktadır. Bu çalışmada, sahip olduğu mükemmel korozyon direnci, yüksek dayanım/ağırlık oranı ve biyouyumluluk gibi üstün özelliklerine karşın zayıf aşınma direnci nedeniyle kullanım alanları kısıtlanmakta olan saf titanyumun (Kalite 2) yüzeyine PVD yöntemi kullanılarak CrN kaplanmıştır. Kaplanmış ve kaplanmamış numunelerin aşınma davranışları tribolojik uygulamalar için incelenmiştir. CrN kaplanmış numunelerin yüzey morfolojisi ve mikroyapısı XRD ve SEM cihazları yardımıyla incelenmiştir. Aşınma deneyleri pin-on-disk cihazında yapılmıştır. Çalışma sonucunda, CrN kaplanmış numunelerin kaplanmamış numunelere göre daha yüksek yüzey sertliğine ve daha iyi aşınma direncine sahip olduğu görülmüştür

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• MakaleYalnız künye2016/r/gumushane/15245
  Influence of CrN Coating on Electrochemical Behavior of Plasma Nitrided Pure Titanium in Bio-simulated Environment

  Çelik, Ilhan

  Titanium and its alloys are widely used as materials for bio-medical applications, such as implants. However, ions of the alloy can release to the body region and spread into the blood circulation. In this study, plasma nitriding and CrN coating techniques are used in order to overcome the problem of ion release. The objective of this study was to investigate the effects of plasma nitrided pure titanium on the structural properties and corrosion behaviors before and after CrN coating in Ringer's solution at 37 °C. The structural properties were investigated using Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD). A diffusion layer and a compound layer composed of δ-TiN and ε-Ti2N phases were observed on the surface of nitrided pure titanium. Corrosion tests were made for the determination of electrochemical properties with the help of Potentiostat/Galvanostat device. The results show that corrosion behaviors of untreated and treated samples have similar characteristic.

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• MakaleAçık Erişim2016/r/gumushane/15241
  Investigation of structural and tribological properties of duplex surface treated pure titanium

  Çelik, I.; Karakan, M.

  Commercial pure titanium (CP-Ti) is used in many engineering fields because of its superior properties such as excellent corrosion resistance, high strength/weight ratio, and biocompatibility. However, it is not available at the desired rate, since the CP-Ti has poor wear resistance. For this reason, many surface treatments have been applied to improve the poor tribological properties of the CP-Ti. In this study, duplex surface treatments, which are the combination of treatments of electroless Ni-B coating and plasma nitriding, were applied on the surfaces of the CP-Ti. Structural properties of the different surfaces of the treated materials were investigated using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Microhardness measurements were made for the determination of mechanical properties and the pin-on-disk wear tests were made to determine the tribological properties. It was observed that poor wear resistance of the CP-Ti was improved with duplex surface treatments. The results showed that surface hardness, friction coefficient, and surface roughness of coated samples were better than of uncoated CP-Ti.

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