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Öğe The Effect of Aging and Sliding Speed on Wear Behaviour of Cu-Cr-Zr Alloy(Carl Hanser Verlag, 2013) Ozyurek, Dursun; Ciftci, Ibrahim; Tuncay, TanselIn this study, the sliding wear behaviour of non-aged and aged Cu-Cr-Zr alloy specimens were investigated. The specimens were aged for 2 h at the temperatures of 450 degrees C and 475 degrees C. Prior to the wear tests, microstructural examinations and hardness measurements were performed on all Cu-Cr-Zr alloy specimens. The wear tests were performed on a pin-on disk type wear apparatus at the sliding speeds of 0.5 ms(-1), 1.0 ms(-1) and 1.5 ms(-1) as well as under 40 N applied load. After the wear tests, the worn surfaces of all samples were analyzed by SEM and energy dispersive X-ray spectroscopy (EDS). The experimental results indicated that aging heat treatment led to increase in the hardness values of Cu-Cr-Zr alloys and the highest wear loss was observed for non-aged specimens. With increasing sliding speed, the wear loss increased to a maximum value beyond which it decreased.Öğe Effect of Cu Content on Microstructure and Wear Behaviour in A356 Alloy(Gazi Univ, 2016) Tuncay, TanselIn this study, A356 alloys with various amount of Cu (0.1-0.4 wt. %) were produced by casting and the effects of Cu content on the microstructure and wear behaviour of these alloys were investigated. T6 heat treatment was applied to the produced A356 alloys. The microstructures of the produced A356 alloys were examined by optical microscope (OM), scanning electron microscopy (SEM), X-Ray diffraction analysis (XRD) and hardness measurements. Wear tests were carried out on a pin-on disk type wear apparatus at 1 ms(-1) sliding speed for different sliding distances (500, 1000, 1500 and 2000 m) under different loads (10, 20 and 30 N). The results showed that the morphology of Al-Si eutectic was refined and distributed uniformly in the microstructure with increasing Cu amount. In addition, iron-based intermetallic phases formed in the microstructure were also seen to be refined. With increasing Cu amount added to A356, the amount of Al2Cu precipitates (due to aging) and the hardness values of the alloys increased. According to the wear test results, while the lowest wear rates were obtained for A356 alloys with 0.2% and 0.4% Cu under 10 and 20 N loads, the lowest wear rate under 40 N load was obtained for A356 alloy with 0.4% Cu content.Öğe THE EFFECT OF DIFFUSER AND NON-DIFFUSER RUNNER SYSTEMS ON THE MECHANICAL PROPERTIES OF A356 ALLOY(Gazi Univ, Fac Engineering Architecture, 2013) Tuncay, Tansel; Tekeli, Suleyman; Ozyurek, DursunIn this study, runner systems which have equal cross-sectional area and different forms of cross-sectional diffuser and non-diffuser runner system's effects on mechanical properties of A356 aluminium alloy, depending on the movement of the liquid metal, were investigated. The aim of the study is to reduce casting defects due to inclusion caused by runner systems such as gas or shrinkage porosity. Therefore, the horizontal runners have been extended by using diffusers having cross-sectional area equivalent with a different cross-sectional shape (square, rectangular and circular outlet). Tensile test specimens were prepared from the plates of casting A356 alloy and tensile tests were performed. Obtained results were examined Weibull statistical analysis. As a result, one hand, it is observed that the turbulence effect on liquid metal has been decreased the highest tensile results and Weibull modulus has been appeared on the samples which have horizontal runners produced by using a square section diffuser in designed horizontal diffuser. On the other hand, according to Scanning Electron Microscope (SEM) analysis on fracture surfaces, fracture has been observed in the area of intermetallic secondary phases (oxides etc.) and in area with gas or shrinkage porosity.Öğe The Effect of Iron Content on Microstructure and Mechanical Properties of A356 Cast Alloy(Springer, 2017) Tuncay, Tansel; Bayoglu, SametIn the present study, microstructure and mechanical properties of A356 alloy including various amounts (0.2 to 1.2 wt pct) of iron were investigated. The alloys were produced by conventional gravity sand casting method. In order to determine the effect of iron addition to A356, optical and scanning electron microscopes (SEM/EDS) were used for microstructural examinations, and X-ray diffraction (XRD) analysis was carried out for phase characterization. Tensile tests were also conducted in order to determine effect of the Fe content on mechanical properties. It was found that as the Fe content of A356 was increased, the secondary dendrite arm spacing (SDAS) was decreased and the morphology of Al-Si eutectic became finer. From XRD examinations, different iron-based intermetallic compounds (beta-Al5FeSi and alpha-Al8Fe2Si) formations were observed. It was also observed that as iron content increased, alpha-Al8Fe2Si intermetallic was transformed into beta-Al5FeSi intermetallic. The tensile test results revealed that tensile strength and elongation values were reduced by increasing Fe content. It was also determined that beta-Al5FeSi intermetallics were more negatively effective on tensile strength than alpha-Al8Fe2Si intermetallics.Öğe The Effects of Cr and Zr Additives on the Microstructure and Mechanical Properties of A356 Alloy(Springer India, 2020) Tuncay, Tansel; Ozyurek, Dursun; Dispinar, Derya; Tekeli, SuleymanThis study has investigated the effect of different amounts of Cr and Zr additions on the microstructure and mechanical properties of A356 alloy modified with strontium. The microstructure and phase examination were performed using an optical microscope, scanning electron microscope and XRD analysis, whereas mechanical properties were investigated via tensile testing and hardness measurements. Two-dimensional Weibull distribution was used to determine the effect of Cr and Zr additions on mechanical properties of A356 alloy. It was found that the most significant effect of Cr and Zr added was over the morphology of Al-Si-Fe intermetallics. The addition of Cr and Zr led to the formation of Cr/Zr-based intermetallics in precipitates and fish-bone-like morphologies. It was observed that increasing the amount of Cr and Zr had resulted in an increase in ductility of A356.Öğe Effects of Mold Cavity Geometry on Flow Rate and Mechanical Properties in Al-Si-Mg Alloy(Springer, 2023) Tuncay, Tansel; Baytar, Furkan; Tuncay, Badegul; Sunar, Talha; Dispinar, DeryaIn this study, the effects of the oxide films formed by using different mold cavity geometries on the mechanical properties of the parts were investigated. The casting process was carried out using the same runner system with different mold geometries. The effect of liquid metal flow rate on bifilm formation and the mechanical properties of the cast material were examined. Eventually, oxide bifilms formed in the mold cavity when the flow rate is low (caused by folding). These oxide bifilms negatively affect the mechanical properties as much as the oxide bifilms formed in the runner system. When real-time liquid metal flow rates are examined in different casting cavities, flow irregularities such as turbulence, folding, and splashing were developed differently in the flow rate of the liquid metal. It was determined that the stability in the flow rate of the liquid metal directly affects the mechanical strength.Öğe The Effects of Molding Materials on Microstructure and Wear Behavior of A356 Alloy(Walter De Gruyter Gmbh, 2017) Yildirim, Musa; Ozyurek, Dursun; Tuncay, TanselIn this study, the effect of molding materials on microstructure and wear behavior of A356 alloy was investigated. Different microstructures were obtained by casting A356 alloy into the molds made from three different materials. Homogenization and aging heat treatments were applied as cast blocks. The aged samples were tested by pin-on-disk-type standard wear equipment. The results showed that casting into different mold materials resulted in different microstructures of A356 alloy. Microstructures of the Al-Si-Mg alloy differ depending on the mold materials. Secondary dendrite arm space (SDAS) decreased proportionally with increasing cooling rate. Based on the cooling rate, hardness values of the alloy also differ. As the cooling rate increased, hardness of the alloy increased. The SDAS increased due to the decreasing cooling rate. In wear tests, increasing weight loss was observed with decreasing cooling rate.Öğe The Effects of Nanoparticle Reinforcement on the Micromilling Process of A356/Al2O3 Nanocomposites(Mdpi, 2023) Sunar, Talha; Parenti, Paolo; Tuncay, Tansel; Ozyurek, Dursun; Annoni, MassimilianoImproving scientific knowledge around the manufacturing of nanocomposites is key since their performance spreads across many applications, including those in meso/micro products. Powder metallurgy is a reliable process for producing these materials, but usually, machining postprocessing is required to achieve tight tolerances and quality requirements. When processing these materials, cutting force evolution determines the ability to control the microcutting operation toward the successful surface and part quality generation. This paper investigates cutting force and part quality generation during the micromilling of A356/Al2O3 aluminum nanocomposites produced via powder metallurgy. A set of micromilling experiments were carried out under various process parameters on nanocomposites with different nano-Al2O3 reinforcements (0-12.5 vol.%). The material's ductility, internal porosity, and lack of interparticle bonding cause the cutting force generation to be irregular when nanoparticle reinforcements were absent or small. Reinforcement ratios higher than 2.5 vol.% strongly affect the cutting process by regularizing the milling force generation but lead to a proportionally increasing average force magnitudes. Hardening due to nano-reinforcement positively affects cutting mechanisms by reducing the plowing tendency of the cutting process, resulting in better surface quality. Therefore, a threshold on the nano-Al2O3 particles' volumetric loadings enables an optimal design of these composite materials to support their micromachinability.Öğe The Effects of T5 and T6 Heat Treatments on Wear Behaviour of AA6063 Alloy(Walter De Gruyter Gmbh, 2014) Ozyurek, Dursun; Tuncay, Tansel; Kaya, HasanIn this study, T5 heat treatment was applied to AA6063 alloy aged at 455 K for 2 hours after extrusion at 686 K. T6 heat treatment was also carried out by ageing at 455 K for 2 hours after solution heat treatment at 794 K for 1 hour. Heat treated T5 and T6 specimens were tested by pin-on-disc type wear equipment. Wear test was carried out by using 10, 20, 30 N loads and 400, 800, 1200 and 1600 m wear distance. T5 and T6 heat treated specimens were characterized with scanning electron microscope, X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and hardness measurements. Worn surfaces of the specimens was also characterised with SEM. The results indicated that small and homogenously dispersed Mg2Si precipitates formed in AA6063 aluminium alloy with T6 heat treatment were compared to the T5 heat treatment. As a result of increment precipitate size, wear resistance decreased. T6 heat treated specimens showed higher hardness compared to the T5 heat treated specimens. In addition wear resistance and friction coefficient of both T5 and T6 heat treated specimens decreased with increasing applied load.Öğe THE EFFECTSON MICROSTRUCTURE AND MECHANICAL PROPERTIES OF FILTRATION IN Al-Si-Mg ALLOYS(Gazi Univ, Fac Engineering Architecture, 2014) Tuncay, Tansel; Ozyurek, DursunIn this study, on microstructure and mechanical properties of Al-Si-Mg alloy was investigated effects of ceramic foam filters having different density of cell. Ceramic foam filters is used to minimizing bifilm, inclusion, sand wash away from of the mould wall, gas or shrinkage porosity such as casting defects. As a result of the tensile test results were evaluated with Weibull distribution and the quality index. Mechanical properties and castability were examined by ceramic foam filters using in Al-Si-Mg alloy. Experimental studies were used on horizontal runner a ceramic foam filter having different density of cell (20 and 30 ppi). According to Tensile test results, due to the increased density of ceramic foam filter cell gap could be controlled flow behaviour of the liquid metal in the running system. Improving mechanical properties of Al-Si-Mg alloy has been demonstrated by increasing Weibull modulus and quality index. In addition to increasing the amount of cell gap in ceramic foam filter, quality index is also increasing. Tensile fracture surfaces of samples was investigated Scanning Electron Microscope (SEM), to fracture occurs secondary intermetallic phases, inclusion and bifilm defect concentration regions.Öğe Experimental investigation and prediction of wear properties of Al/SiC metal matrix composites produced by thixomoulding method using Artificial Neural Networks(Elsevier Sci Ltd, 2014) Ozyurek, Dursun; Kalyon, Ali; Yildirim, Musa; Tuncay, Tansel; Ciftci, IbrahimIn this study, the wear properties of the SiC particle reinforced aluminium (A356) composite materials (MMCs), produced with thixomoulding method, were investigated both by experimental and Artificial Neural Network (ANN) model in order to determine the weight loss after the wear tests. Two different temperatures (590 degrees C and 600 degrees C) were used in production of the MMCs containing 5%, 10%, 15% and 20% SiC (vol%). The samples of MMC were tested at 2 ms (1) constant sliding speed under 30 N and 60 N loads against four different sliding distances (500 m, 1000 m, 1500 m, and 2000 m). The results indicated that by increasing the production temperature increased the grain size of the MMCs was increased, but the hardness was decreased. The MMCs produced at 590 degrees C were found to have lower weight loss as compared with ones produced at 600 degrees C. In the theoretical prediction model of the MMCs, weight loss, SiC per cent, production temperature, applied weight and sliding distance were used as input values. After comparing the experimental results and the ANNs predicted data it was observed that R-2 was 0.9855. This shows that the developed prediction model has a high level of reliability. (C) 2014 Elsevier Ltd. All rights reserved.Öğe Influence of casein on the degradation process of polylactide-casein coatings for resorbable alloys(Nature Portfolio, 2024) Cesarz-Andraczke, Katarzyna; Staszuk, Marcin; Tuncay, Tansel; Wozniak, Anna; Smok, Weronika; Tuncay, BadegulThis study used the dip-coating method to develop a new biocompatible coating composed of polylactide (PLA) and casein for ZnMg1.2 wt% alloy implants. It evaluated its impact on the alloy's degradation in a simulated body fluid. After 168 h of immersion in Ringer's solution, surface morphology analysis showed that the PLA-casein coatings demonstrated uniform degradation, with the corrosion current density measured at 48 mu A/cm2. Contact angle measurements indicated that the average contact angles for the PLA-casein-coated samples were below 80 degrees, signifying a hydrophilic nature that promotes cell adhesion. Fourier-transform infrared spectroscopy (FTIR) revealed no presence of lactic acid on PLA-casein coatings after immersion, in contrast to pure PLA coatings. Pull-off adhesion tests showed tensile strength values of 7.6 MPa for pure PLA coatings and 5 MPa for PLA-casein coatings. Electrochemical tests further supported the favorable corrosion resistance of the PLA-casein coatings, highlighting their potential to reduce tissue inflammation and improve the biocompatibility of ZnMg1.2 wt% alloy implants.Öğe Influence of technological synthesis conditions on corrosion behaviour and mechanical properties for NiTi alloys(Emerald Group Publishing Ltd, 2023) Tuncay, Badegul; Cug, Harun; Tuncay, Tansel; Ozyurek, Dursun; Cesarz-Andraczke, KatarzynaPurposeThis study aims to investigate NiTi alloys' characterization and corrosion behaviour produced by two different powder metallurgy (PM) methods. Design/methodology/approachIt was pre-formed under a protective atmosphere at 900 & DEG;C under a force of 45 MPa and sintered for 1 h under 10-6 Mbar in an atmosphere-controlled heat treatment furnace at 1,100 & DEG;C. The relationship between microstructural properties, SEM, XRD, density, microhardness and corrosion behaviour of pre-alloyed NiTi alloys produced by two different methods with the production method was investigated. FindingsAs a result of the studies, TiO, NiTi, NiTi2 and Ni3Ti intermetallics were determined in XRD examinations. The best surface roughness was observed in the mechanically milled (MM'ed) pre-alloyed NiTi alloy compared to the pre-alloyed NiTi alloy mixed with turbula. The corrosion tests performed in 3.5% NaCl solution determined that the MM'ed pre-alloyed NiTi alloy had better corrosion resistance than the pre-alloyed NiTi alloy mixed with turbula. Pitting corrosion was visualized in the SEM images taken from the corrosion surfaces. Originality/valueTwo different PM methods produced pre-alloyed NiTi powders, and the effects of these methods on the mechanical and corrosion resistance of NiTi alloys were systematically investigated for the first time.Öğe Microstructural and Mechanical Properties of A356/Ni Alloys Produced by the Mechanochemical Method(Pleiades Publishing Inc, 2022) Tuncay, TanselIn this study, A356 powder was alloyed with elemental Nickel (Ni) powder in different ratios using a mechanochemical alloying method. Alloyed A356/XNi powders were cold pressed along one axis under a load of 350 MPa and sintered at 600 degrees C. To determine the effect of intermetallic phases formed on the microstructure in proportion to the amount of Ni, the A356/XNi alloys were characterized by X-ray diffraction (XRD) analysis, density, and microhardness values. As a result, after mechanical alloying, the spherical microstructure of the A356 alloy turned into a spongy form due to the sponge-like Ni elemental powders. After sintering, it was determined by optical microscopy and scanning electron microscopy (SEM) examinations that the grain size of A356/XNi alloys increased with an increasing amount of Ni. In addition, it was determined that the relative density and amount of porosity increased with an increasing amount of Ni. According to the XRD analysis results, it was determined that AlNi, Al3Ni2, Al3Ni and AlFeNi intermetallic phases formed in the microstructure due to the mechanochemical and sintering process.Öğe Microstructure-bifilm interaction and its relation with mechanical properties in A356(Taylor & Francis Ltd, 2017) Tuncay, Tansel; Tekeli, Suleyman; Ozyurek, Dursun; Dispinar, DeryaCooling conditions and inclusions are of the most important factors that affect mechanical properties of cast aluminium alloys. This study investigated the effect of secondary dendrite arm spacing (SDAS) on the shape of pores (i. e. bifilm unravelling) and the mechanical properties of cast A356 alloy. Different cooling conditions were established by electrolytic copper chill, H13 steel chill and insulated ceramic that was placed in the mould cavity. SDAS and shape of pores were investigated by optical microscopy. The fracture surfaces of tensile test samples were analysed by SEM and EDX. Weibull two-parameter statistical method was used to assess the tensile properties. Results show that mechanical properties were dominantly affected by pore morphology that was formed by bifilms. Increasing the cooling rate (i. e. decreasing SDAS), the unravelling of bifilms delayed which decreased porosity formation significantly.
