Kuleyin, Hamdi; Budak, Selahattin; Yasan, Ömer Barışkan; Gümrük, Recep

The polymer blending method is widely used to obtain balanced mechanical properties and structural performance in many engineering applications. This study investigates the influence of Ethylene-Vinyl Acetate (EVA), and Thermoplastic Polyurethane (TPU) composition ratios on the thermal, chemical, viscoelastic, mechanical, and fatigue life behavior of Acrylonitrile-Butadiene-Styrene (ABS) based elastomeric blends. For this purpose, structural and mechanical properties of the blend material depending on their composition ratio were carried out through a series of characterization analyses, and tensile and fatigue tests. The findings indicated that ABS/EVA and ABS/TPU blends formed an immiscible structure. In addition, it was determined that the storage modulus of the blend with 10 % TPU improved because of the presence of new absorption peaks in the structure. The mechanical properties such as elastic modulus, yield strength, and ultimate tensile strength decreased concerning neat ABS with an increase in the EVA and TPU composition ratio for blend materials. However, the elongation to break was achieved approximately 6 times increasing with an increase in the TPU ratio for ABS/TPU blends. It was determined that the fatigue strength value in ABS/EVA and ABS/TPU blends decreased with the decrease in ABS composition ratio in the blend system. However, it was found that fatigue life improved by 25 % compared to ABS at low-stress amplitude for 10 % TPU additive. Finally, it can be revealed that the ABS-based elastomeric blends can be used to obtain desired properties according to their composition ratios for different applications.

Başyipit, Aziz Bariş; Azakli, Zeki; Gümrük, Recep; Bican, Osman

The efficiency of thorough anodic oxidation of ASTM A356 aluminum alloy as an alternative to painting its surface is studied. Microstructure, phase composition, and microhardness of oxidized layers of various thicknesses (45, 65, 80 and 90 μm) are determined. Solid particle erosion tests are conducted in accordance with ASTM G76 and MIL STD 3033. It is established that with an increase in oxidized layer thickness aluminum alloy wear resistance is reduced and the surface roughness is reduced.

Azakli, Zeki; Gümrük, Recep

Many critical parts such as surface parts of high-speed trains, bins and hoppers, and pipes, bends and valves in material transportation applications as well as a helicopter, mixer, and turbine blades, which can be exposed to particle wear due to the application environment, can be easily manufactured today due to the advances in 3D printing technology. For this reason, an experimental study was carried out to determine the particle erosion behavior of 316L stainless steel parts built by the laser melting method, which is one of the 3D printing technologies. The rectangular plate samples produced with various laser manufacturing parameters were subjected to particle erosion tests at different impingement angles in accordance with the ASTM G76 standard at 140 m/s impact speed. The results showed that the erosion behavior develops in a characteristic similar to the wrought sample, and laser parameters play an efficient role. For example, the porosity ratio decreases at low scanning speeds, resulting in significant improvements in erosion behavior. Also, it was found that the particle erosion behavior of the 3D printed parts could be improved in a serious amount by applying a heat treatment process. Consequently, the obtained results in this study promotes the more comprehensive works regarding the optimization of several laser manufacturing parameters such as scan speed, build direction, laser power, hatch spacing, layer thickness, scan strategy and laser exposure time to obtain the best particle erosion behavior and determination of the most suitable materials among the several others which can be used in 3D printing.

Mazlum, Uğur; Gümrük, Recep

Ferromanyetik toz partikülleri, manyetik alana duyarlılıklarından dolayı günümüzde pek çok alanda kullanılmaktadır. Bu tozların matris malzemeleri ile birleşimlerinden elde edilen kompozit MRE malzemeler sınıflandırılmaktadır. Bu çalışmada, RTV (room temperature vulcanization) silikon kauçuğuna dört farklı manyetik toz ilave edilmesi ile elde edilen kompozit MRE malzemelerinin bası yüklemesi altındaki mekanik özelliklerinin incelenmesi amaçlanmıştır. Matris malzemesi olarak mühendislik açıdan kullanımı yaygın olan Vario 40 silikon kauçuk malzemesi kullanılmıştır. Kompozit MRE malzemelerde toz oranı hacimce %30 oranında tutulmuştur. Ayrıca, tozların yönlenmesinin etkisini incelemek için, üretim esnasında bazı numunelere dış manyetik alan uygulanmıştır. Bu numuneler anizotropik olarak adlandırılırken diğerleri izotropik numunelere olarak adlandırılmıştır. Sonuçlar göstermiştir ki; anizotrop MRE numuneler izotrop numunelere göre çok daha yüksek gerilme değerlerine sahip olmaktadır ve en büyük gerilme artışı BASF CN tozu ilave edilen anizotrop MRE malzemeler için elde edilmiştir. Ayrıca, numuneler MR etki açısından da değerlendirildi ve izotropik versiyonlarına göre %201 gibi bir artış değeri ile en büyük MR etki SQI tozu içeren anizotrop numunelerde gözlemlendi. Sonuç olarak, gerçekleştirilen çalışma ile MRE malzemelerin mekanik ve MR özellikleri, ilave edilen tozun cinsi ve manyetiklik özelliklerine ciddi bir şekilde bağlı olduğu belirlenmiştir

Mazlum, Uğur; Gümrük, Recep

Magneto-rheological Elastomers are smart materials whose properties can be altered reversibly and almost instantaneously by application of external magnetic fields. Silicone rubber species are used widely in the laboratory studies because of it is easy to prepare and cured at room temperature. In this study, MRE material was produced using three different types of silicone rubber and ferromagnetic powder which is sensitive to magnetic field. MRE materials are obtained as isotropic (homogenous) and anisotropy (aligned) state. Composite materials were tested in uniaxial compression testing machine with three different test procedures. In this way, the mechanical properties and the magneto-rheological effect of the materials were compared. As a result, under the magnetic field to 0.430 T with anisotropic Sorta Clear40 materials were found to increase in stress 30%, according to the pure state has been demonstrated that the rate of 50%. When the isotropic Sorta Clear40 and Vario40 materials were comparable, MR effect was revealed that the increases the rate of about 325% at strain to 5%. When selecting to optimum rubber types was reached the result should be used to materials the most appropriate to the material characteristics of engineering aspects.

Mazlum, Ugur; Gümrük, Recep

The ferromagnetic particle, are used in many areas due to their magnetic field sensitivity. Composite MRE materials which obtained from the combination of the matrix material with these particles are classified as a kind of smart materials. In this study, it is aimed that the compressive mechanical properties of MRE materials produced by adding four different magnetic particles in RTV (room temperature vulcanizing) silicone elastomer are investigated. As a matrix material Vario 40 silicone rubber were used, which is common in engineering application. The particle rate inside MRE materials was kept at 30% by volume. In addition, to investigate the influence of orientation of particles inside MRE materials, some samples were subjected to external magnetic field during production. These samples are named as anisotropic MRE materials while the others are described as isotropic ones. The tests showed that anisotropic samples have much more strength values according to isotropic samples. Of all, the MRE samples including BASF CN particles reveal the biggest strength values. Also, the samples were evaluated in terms of MR effect and the largest MR effect with an increase value of 201% was found for anisotropic samples including SQ-I particles with regard to the corresponding isotropic one. As a result, this study determined that the mechanical and MR properties of MRE materials seriously depend on ferromagnetic particle kind and its magnetic characteristic.

Mazlum, Ugur; Gümrük, Recep

Magneto-rheological (MR) materials are in a smart material class that has the rheological properties to be quickly and reversibly controlled with the external magnetic field applications. Considering the technological developments the rubber-like smart materials has had a more functional usage area with magneto-rheological effect. This study investigates the axial mechanical properties of magneto-rheological Ethylene Propylene Diene Monomer (EPDM) and Natural Rubber (NR) type synthetic rubbers for isotropic and anisotropic situations. Also, these composite materials were built by means of hot press systems as either isotropic or anisotropic using magnetic field application after addition of ferromagnetic powders. The influence of magnetic field was investigated. In this study, NR rubber was found to be more susceptible in terms of smart material properties unlike EPDM synthetic rubber.

Gümrük, Recep; Mazlum, Uʇur; Mines, R.A.W.

This article investigates compressive and energy absorption characteristics for composites obtained by filling stainless steel micro lattice materials, manufactured via the selective laser melting method, with three different rubbers, including room temperature vulcanization silicone, natural rubber, and neoprene rubber. At the stage of building the composites with natural and neoprene rubbers, an experimental setup was designed for these two rubbers to be infiltrated into lattice spaces under vulcanization temperatures and high pressures. The results showed that the composites with silicone and neoprene matrix had a quite similar response as well as a seriously enhanced energy absorbing capacity and plateau stresses, in comparison with the corresponding lattice structures, for especially small sized lattice components. Also, the compression tests of the composite with natural rubber matrix clearly show that there should be no large differences between the individual mechanical properties of each component in the composite, and, in this way, the contribution of each component on the mechanical behavior of composite should be guaranteed to provide the satisfying performance.