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Öğe Analysis of optical radiation emissions during GMAW applications(Natsional'na Akademiya Nauk Ukrainy, 2015) Gürsel, Ali; Kurt, AdemThe GMAW (Gas Metal Arc Welding) technique and its radiation emissions are examined in this study. Three commonly used materials in industry, SS304-type stainless steel, A36 low-carbon steel, and T6061 aluminium, are chosen for the tests. The welding is applied at 140 A, and radiation types and luminosities are evaluated for each material. During the welding processes, ultraviolet radiation was the most frequently observed at all parameters; in addition, visible light and infrared radiation, 200-1000 nm on an optical scale, are recorded. The effects of electric currents on the photon energy rates are clearly exhibited. The wavelengths are similar on the SS304 and A36 materials, but higher photon energy and intensity are observed on SS304. Furthermore, for the T6061 aluminium material, the optical radiation emission and peak patterns are totally different from the others, with peaks spiking over the entire range of the optical scale.Öğe COMPARISON OF MANUFACTURING TECHNIQUES SUBJECT TO HIGH SPEED IMPACT(Amer Soc Mechanical Engineers, 2015) Gollins, Kenneth; Chiu, Jack; Delale, Feridun; Liaw, Benjamin; Gürsel, AliIn this paper we compare two manufacturing techniques namely vacuum infusion and compression molding, used in manufacturing S2 glass fabric/epoxy composites for high-speed impact applications. Even though compression molding and vacuum infusion are two widely used manufacturing techniques, the resulting product may be very, different. Compression molding has the advantage of achieving a much higher fiber density for the same thickness. With a higher fiber density, the composites made by compression molding have better mechanical properties than a composite made by vacuum infusion. However, vacuum infusion is faster and more. economical. The mechanical performance of the composites manufactured by these two processes are compared by performing tensile tests and high speed impact tests for the' determination of the limit speed V-50. For the same number of plies, preliminary results for compression molded specimens indiCate a 50% increase in stiffness and a 40% increase in strength. Also, for panels of the same thickness, the V-50 was higher for compression molding specimens.Öğe Corrosion characterization of Sn-Zn solder: a review(Emerald Group Publishing Ltd, 2019) Nazeri, Muhammad Firdaus Mohd; Yahaya, Muhamad Zamri; Gürsel, Ali; Cheani, Fakhrozi; Masri, Mohamad Najmi; Mohamad, Ahmad AzminPurpose The purpose of this paper is to review and examine three of the most common corrosion characterization techniques specifically on Sn-Zn solders. The discussion will highlight the configurations and recent developments on each of the compiled characterization techniques of potentiodynamic polarization, potentiostatic polarization and electrochemical impedance spectroscopy (EIS). Design/methodology/approach The approach will incorporate a literature review of previous works related to the experimental setups and common parameters. Findings The potentiostatic polarization, potentiodynamic polarization and EIS were found to provide crucial and vital information on the corrosion properties of Sn-Zn solders. Accordingly, this solder relies heavily on the amount of Zn available because of the inability to produce the intermetallic compound in between the elements. Further, the excellent mechanical properties and low melting temperature of the Sn-Zn solder is undeniable, however, the limitations regarding corrosion resistance present opportunities in furthering research in this field to identify improvements. This is to ensure that the corrosion performance can be aligned with the outstanding mechanical properties. The review also identified and summarized the advantages, recent trends and important findings in this field. Originality/value The unique challenges and future research directions regarding corrosion measurement in Sn-Zn solders were shown to highlight the rarely discussed risks and problems in the reliability of lead-free soldering. Many prior reviews have been undertaken of the Sn-Zn system, but limited studies have investigated the corrosive properties. Therefore, this review focuses on the corrosive characterizations of the Sn-Zn alloy system.Öğe Crack risk in Nd: YAG laser welding of Ti-6Al-4V alloy(Elsevier Science Bv, 2017) Gürsel, AliThe excellent properties of titanium and titanium alloys, including corrosion resistance, high strength to weight ratio and high operating temperature, have led to their successful application in various fields. However, titanium and its alloys are destroyed by the conventional welding process if welding parameters are not controlled. Laser welding is one of the most reliable methods for use with titanium alloys because of its precision and rapid processing capability. In addition, it enables control of the welding parameters and their effects. In this study, Ti-6Al-4V alloy sheets were welded by Nd: YAG pulsed laser and the potential crack risk on the weld joints was investigated. The optimum results obtained in 3.9 kW peak power, better ductility was obtained from the Grade 1 titanium alloy filling material. (C) 2016 Elsevier B.V. All rights reserved.Öğe Defect Detection Capability of Radiographic Testing on Petroleum Pipe Welds(Düzce Üniversitesi, 2013) Gürsel, AliWelded zone of the petroleum pipes, is the most critical part in terms of resistance like other weld joining. While construction of pipe lines, welding process is done in two steps, one of them is carried out during the manufacturing and the other is installation of the pipes in the land. In manufacture submerged arc welding is used and assembling is done by using manual welding techniques. In this study, weld seams were performed by using submerged arc welding and welding defects were formed intentionally, and these defects were tested by radiographic method. By using fluoroscopy which is one of the tecnic of radiographic methods, the defects were tested and the results were evaluated. It is concluded that these techniques are suitable for manufacturing and assembling of the pipes, but in case of doubt, it’s needed to accurate by another non-destructive testing method.Öğe The Effect of Diffusion Welding Parameters on the Mechanical Properties of Titanium Alloy and Aluminum Couples(Mdpi Ag, 2017) Akça, Enes; Gürsel, AliTi-6Al-4V alloy and commercially pure aluminum, which are commonly used in aerospace, medical, and automotive industries, are bonded by diffusion welding. Different welding parameters (560, 600, and 640 degrees C-0, 45, and 60 min-under argon shielding) are used in this process to make the materials more applicable in the industry. Here, the effects of parameters on the strength of joints were studied. The bonded samples were subjected to microhardness and tensile tests in order to determine their interfacial strength. The hardness values were found to decrease with increasing distance from the interface on the titanium side while it remained constant on the aluminum side. Maximum tensile strength was taken from the maximum bonding temperatures of 600 and 640 degrees C. A morphology examination of the diffusion interfaces was carried out with scanning electron microscopy.Öğe The Effect of Materials on Radiation Exposure during the GTAW Process(Amer Welding Soc, 2014) Gürsel, Ali; Kurt, AdemIn this study, the gas tungsten arc welding (GTAW) technique was used to weld samples of three materials: SS304-type stainless steel, A36 low-carbon steel, and 16061 aluminum. The welding was applied at 200 A, and the radiation types and luminosities were measured for each material. During the welding processes, UV radiation was the most frequently observed in all parameters; in addition, visible light and IR radiation, 200-1000 nm on an optical scale, were recorded. The effects of electric currents on the photon energy rates were clearly exhibited. The production and type of radiation (photon energy and high-frequency energy) were affected by the GTAW applications using tungsten electrodes containing 2% thorium, thus corroborating previous findings in the literature.Öğe Effects of cooling rate on strength and microstructure of powder metallurgy superalloys(International University of Sarajevo, 2017) Yıldız, Gökhan; Gürsel, Ali; Akça, EnesThe excellent mechanical properties of powder metallurgy superalloys strongly depend on the microstructure, grain size, morphology, and size distribution of the ?' precipitates. In this study, the effects of cooling rate on strength and microstructure of powder metallurgy superalloys were investigated. Articles were reviewed about this topic and they all were evaluated. Different types of powder metallurgy superalloys such as FGH4096, U720LI, UDIMET 500, MAR-M247, K465, IN738LC, Rene88DT, CM247LC and K5 were selected for this study. These materials were tested in different parameters (temperature and time) and different cooling rates were applied. Test results showed that cooling rate has considerable effects on strength and microstructure of powder metallurgy superalloys. It was observed that the strength increased by the increment of cooling rate. Also, almost homogeneous microstructure was obtained at high cooling rate.Öğe FUNDAMENTALS IN ADHESIVE BONDING DESIGN FOR COMPLEX STRUCTURES AND CONDITIONS: AN OVERVIEW(Düzce Üniversitesi, 2019) Gürsel, AliThe importance of assembling technologies are rising up in the manufacturing industry. With the development of new materials and their complex structures, new manufacturing and joining technologies are needed. Adhesively bonding techniques are meeting the industrial and technological needs, these techniques are providing an alternative for joining technology andenabling the use of a wider range of materials in product design; and adhesives allow enhanced aesthetics, lighter weight constructions and improved end performance, and also their usefulness build the utilization of multi-material, hybrid structures and for joining of dissimilar materials. Different materials have different physical and mechanical properties. Therefore, processing and joining procedures can also be challenging due to their properties. Adhesive bonding techniques are giving chance to cope with these difficulties. This paper reviews and summarizes state of the art research in adhesive joints for industrial applications in developing the innovative field. This is due to the expanding desires for more capability of strength and light-weight materials.Öğe Influences of argon gas shielding on diffusion bonding of Ti-6Al-4V alloy to aluminum(Cenim, 2017) Akça, Enes; Gürsel, AliThis study presents a diffusion bonding process of commercially pure aluminum to Ti-6Al-4V alloy. Prepared samples were exposed to temperature of 560, 600 and 640 degrees C for the bonding time of 30, 45 and 60 min at the atmosphere of argon gas and non-argon. Diffusion bonding is a dissimilar metal welding process which can be applied to the materials without causing any physical deformations. The processed samples were also metallographically prepared, optically examined followed by Vickers microhardness test in order to determine joint strength. Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) were used in this work to investigate the compositional changes in order to observe the influence of atmosphere shielding in the transition zone. The result of tests and analyses were tried to be compared with the effect of argon shielding. The significant influences have been observed in the argon shielding during diffusion bonding process.Öğe Radiation Emission during SMAW Applications on SS304 and A36 Steels(Carl Hanser Verlag, 2014) Gürsel, Ali; Kurt, AdemHigh energy radiation is produced during arc welding applications. For this reason, it is important to investigate the process in detail with respect to the welding technique, electrical current and materials. In this study, the SMAW (shielded metal arc welding) technique was used to weld specimens made of stainless steel SS304 and of low carbon steel A36. Welding currents of 90, 105, 120 and 135 A were selected. The radiation types and luminosities were measured for each material as well as the respective magnitude of electrical current. During the welding applications, UV radiation was mostly observed. In addition, visible light and IR radiation in the range of 200 to 1000 nanometers on the optical scale were recorded. The effects of electric currents on the photon energy rates were clearly pronounced. A larger radiation energy was observed for the UV band for welding both materials at all parameters.Öğe A review on devulcanization of waste tire rubber(International University of Sarajevo, 2018) Gürsel, Ali; Akça, Enes; Şen, NuriRubber has become an indispensable material for the technological development of civilization, including simple balloon and complex rocket propellant. Rubber Industry worldwide is using on an average 50% of raw materials. These materials were mostly petroleum-based, except natural rubber (NR), steel cord and bead wire. Using of these petroleum-based raw materials not only depletes natural resources, but also produces more extreme environmental hazards. The waste tire rubber problem is of great magnitude and has far reaching environmental and economic implications. There are some ways for recycling of rubber, such as reclaiming technology, surface treatment, grinding and pulverization technology, devulcanization technology. Methods of devulcanizing rubber (or elastomers) have been researched almost since the time of the discovery of the rubber/sulfur vulcanization process. By devulcanization process the cross-links in the structure of rubber are broken and devulcanized rubber can be revulcanized into a raw material for rubber industry, which is a highly valued form of waste rubber. This study provides a review of the recent advances in understanding of methods of recycling rubber and claims that the capacity of thermomechanical and mechanochemical devulcanization methods of recycling waste tire rubber can be improved in future studies. © 2018 International University of Sarajevo.Öğe The wear treatment by Nd:YAG laser on Ti-6Al-4V alloy: Effect of the spot size on laser beam and seam morphology(Natsional'na Akademiya Nauk Ukrainy, 2015) Gürsel, AliDue to the excellent corrosion resistance, high strength to weight ratio and high operating temperature, titanium and titanium alloys lead to successful application in various fields including the medical and aerospace industries. Among the reliable treatments techniques, laser weld can provide a significant benefit for the titanium alloys because of its precision, rapid processing capability and controlling the parameters with their effects. The Nd:YAG laser parameters, such as spot size and shape, pulse energy and duration, travel speed, peak power and frequency of repetition, influence directly or synergistically the quality of pulsed seam welds and their morphology. In this study, 1.5 mm thick titanium Ti6Al4V alloy sheet surfaces are treated by SigmaLaser®300 type Nd:YAG pulsed laser. The influence of spot size on seam morphology and effects to the surface are investigated. The seam and surface quality is characterized in terms of weld morphology and microhardness.Öğe Yapıştırıcı Birleştirmelerde Bağlantı Mukavemetini Etkileyen Faktörler: Yüzey Morfolojisi ve Yüzey Enerjisi(2021) Yıldız, Salih; Gürsel, Aliİmalat sektöründe birleştirme teknolojilerinin önemi artarak devam etmektedir. Birleştirme teknolojileri yarı mamül ürün birleştirmelerinden kompleks yapılar ve kompozit malzeme üretimleri, eklemeli imalat teknolojilerine kadar her alanda kullanılmaktadır. Bu kapsamda, yapıştırıcılar vasıtasıyla yapılan birleştirme teknolojileri farklı cins malzemelerin birleştirmelerine olanak sağladığı gibi, birleştirilecek malzemelerde deformasyona sebep olmadığından büyük avantajlar sağlamaktadır. Yüksek mukavemekli yapıştırıcı uygulamalarında en önemli işlem yüzey hazırlama süreçleridir. Yapışma mekanizmalarında da en yaygın kabul gören ve ispatlanmış teori mekanik kilitlenmedir. Yüzey hazırlama süreçlerinde, malzemelerin optimum yüzey pürüzlülüğüne sahip olmaları durumunda, bağlantılardan istenen mukavemet değerleri elde edilebilir. Yapıştırıcı bağlantılarda birleştirilecek malzemelerin yüzey enerjisi, hem yapıştırıcı reçineyi absorbe etme, hem de yapıştırıcıyla bağ oluşturma bakımından büyük önem taşır. Yüzey hazırlamada uygun yüzey morflojisi ile birlikte yüzey enerjisini arttırıcı işlemler göz gönünde bulundurulmalı ve uygulanmalıdır.
