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Öğe Dry Sliding Wear Behaviour and Microstructure of the W-Ni-Fe and W-Ni-Cu Heavy Alloys Produced by Powder Metallurgy Technique(Springer, 2016) Kilic, M.; Ozyurek, D.; Tuncay, T.The effects of Fe and Cu on the wear behaviour of W-Ni alloys is investigated. W-Ni-Fe and W-Ni-Cu alloys are produced with six different compositions by the powder metallurgy technique. The microstructure is examined after shaping and sintering. Electron microscopy (SEM+EDS) and X-ray diffraction (XRD) are used to characterize the density, hardness, and grain size of W-Ni-Fe and W-Ni-Cu alloys produced by powder metallurgy technique. A pin-on-disc apparatus is used for the wear tests. All of the samples are tested under loads of 20 and 30 N, at a rate of 1 m/s and for five different sliding distances. It is found that, in Fe and Cu alloys, an increase in the W amount results in an increase in density and hardness. Furthermore, an increase in the W amount leads to a decrease in the amount of the binding phase for W-Ni-Fe and W-Ni-Cu alloys with a W content of 90, 93, and 97%, and resultes in reduced weight loss for W-Ni-Fe alloys.Öğe The Effect of Ageing Temperature in T6 Heat Treatment on Mechanical Properties of AA7075(Polish Acad Sciences Inst Physics, 2019) Simsek, I.; Simsek, D.; Tuncay, T.; Ozyurek, D.In this study, the effect of ageing temperatures in T6 heat treatment on the microstructural changing and mechanical properties of AA7075 were investigated. The samples were quenched after solution treatment at 485 degrees C for 2 h. The natural ageing was applied for 1 h, and then artificial ageing was carried out at five different temperatures (100-140 degrees C) for 24 h. Hardness measurements, microstructure, X-ray diffraction examinations, and tensile tests of aged samples were carried out. As a result of the study, the hardness values and ultimate tensile stress values were increased by increasing ageing temperatures up to 120 degrees C. Then it was decreased by increasing ageing temperature. Ultimate tensile stress values were compatible with hardness values and maximum ultimate tensile stress values were obtained in aged samples at 120 degrees C.Öğe The Effect of Modification and Grain Refining on the Microstructure and Mechanical Properties of A356 Alloy(Polish Acad Sciences Inst Physics, 2017) Tuncay, T.In this study, microstructure and mechanical properties of modified (Al10Sr) and grain refined (Al5TiB) A356 aluminum alloy were investigated. To determine the effect of modification and grain refining on the microstructure and mechanical properties of A356 alloy, density measurement, optical microscope and scanning electron microscope examinations and tensile tests were performed. As a result of the study, the highest density and the least percentage of porosity were measured for the modified (with Al10Sr) and grain refined (with 1.5% Al5TiB) alloy system. The lowest density values and the highest percentage of porosity were measured for the unmodified and non-grain refined alloy. According to the tensile tests, average ultimate tensile strength and the highest elongation were obtained for the alloy modified with Al10Sr and grain refined with 1.5% Al5TiB alloy. It was determined that average ultimate tensile strength and percentage of elongation increased as the amount of Al5TiB added for grain refinement and modified to A356 alloy increased.Öğe The effect of Ni addition on microstructure and mechanical properties of cast A356 alloy modified with Sr(Redakcia Kovove Materialy, 2021) Ozyurek, D.; Yildirim, M.; Yavuzer, B.; Simsek, I; Tuncay, T.In this study, casting A356 alloy was pre-alloyed with Ni, and the modification process with Sr was applied by the casting method. The role of Ni on the microstructural and mechanical properties of the produced A356-Ni alloys was investigated. The produced alloys were naturally aged at room temperature for 24 h and artificially aged at 170 degrees C for 10 h. Optical microscopy (OM), scanning electron microscopy (SEM), and X-ray diffractometer were used in microstructure studies of the A356-Ni alloys. Tensile tests and hardness measurements were carried out to determine mechanical properties. Statistical analysis of Weibull distribution on the tensile test results revealed that the characteristic ultimate tensile strength increased due to increasing the amount of alloying elements, while the characteristic percentage elongation is decreased. This was because Al-Si-Fe intermetallic decomposition and Al-Si-Fe-Ni intermetallics were formed, primarily, 0.5 and 1.0 % Ni addition. It was also determined that the Al-Si-Fe-Ni intermetallics with a morphology non-sharp corners formed more homogeneous in the microstructure. But in the A356 alloys with the addition of 1.5 % Ni, Al-Si-Fe-Ni intermetallics are formed in coarser morphology. In A356 alloys, aluminium dendrites, Al-Si eutectic between dendrites, Mg2Si precipitates are formed in the structure by ageing. Depending on the amount of Ni added to the A356 alloy, the tensile strength of the alloys containing 0.5 and 1.0 % Ni is increased.Öğe THE EFFECT OF THE AMOUNT OF Y2O3 DOPED TO THE MA6000 ALLOY PRODUCED BY MECHANICAL ALLOYING METHOD ON WEAR BEHAVIOR(Technical Faculty, Bor-Serbia, 2022) Celik, S.; Ozyurek, D.; Tuncay, T.This paper investigated the wear performances of Y2O3 doped MA6000 (Ni-Cr-Al) alloy produced by mechanical alloying (MA). Produced, all powders were pre-formed by cold pressing and sintered in a vacuum environment. Sintered MA6000-X% Y2O3 superalloys were characterized by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD) analysis, density, and hardness measurements. Wear tests of Y2O3 added MA6000 alloys were carried out in a block-on-ring type wear device. In the wear tests, the sliding speed of 1 ms-1 at room temperature (RT) was performed under five different sliding distances (200-1000 m) and three different loads (5 N, 10 N, and 15 N). As a result of the studies, it was determined that the MA-ed MA6000 superalloy powders were homogeneous and flake shape. With the increase amount of Y2O3, hardness of these superalloys increased from 267 to 431 Hv, but the density slightly decreased. Different intermetallic/carbur phases such as Ni3Al and MoC were observed in all compositions. Wear tests show that weight loss and wear rate decreased, and friction coefficient (mu) increased with the increasing amount of Y2O3 additive. Besides, it was determined that as the applied load increased in the wear test, the weight loss increased, but the wear rate and friction coefficient (mu) decreased.Öğe The effects of Cu and Al on dry sliding wear properties of eutectic Sn-9Zn lead-free solder alloy(Taylor & Francis Ltd, 2016) Ozyurek, D.; Yavuzer, B.; Tuncay, T.The present study investigates the influence of Cu and Al on microstructure and wear behavior of a eutectic Sn-9Zn solder alloy. The Sn-9Zn-X alloy was produced by adding various amounts of Cu and Al through investment casting method. The produced Sn-9Zn-X alloys were characterized by a scanning electron microscope, X-ray diffraction, and hardness measurements. In wear tests at 1ms(-1) sliding speed, 10N load and 5 different sliding distances (400-2000m) were used. The results show that as the amount of Cu and Al increased within Sn-9Zn alloy, the hardness of the alloy increased as well. Depending on the increase in hardness of the alloys produced by investment casting, it was observed that weight loss decreased during wear tests. Furthermore, the same proportion of added Al alloys' hardness and weight loss were observed to be higher than the added Cu alloys. Furthermore, the Cu-added alloy exhibited higher hardness and lower weight loss than the Al-added alloy did.Öğe Exchange of experience the effect of synthesis time on the wear behavior of Al-8%Ti alloy produced by mechanical alloying(Springer, 2012) Ozyurek, D.; Tekeli, S.; Tuncay, T.; Yilmaz, R.In this study, Al-8%Ti alloy was produced by mechanical alloying. The produced powders were cold pressed at 630 MPa and synthesized at 600A degrees C for 12 and 24 h under argon gas atmosphere. After synthesis processes, the specimens were examined by SEM, XRD, and hardness tests. Wear tests were carried out under dry sliding conditions using a pin-on-disk type machine at a constant load of 30 N and a sliding speed of 1 m/sec. Total sliding distances were selected as 500, 1000, 1500, and 2000 m. The experimental results showed that the hardness and density of Al-%8Ti alloy increased with increasing synthesis time. It was also observed that volume reduction increased with increasing sliding distance and decreased with increasing synthesis time.Öğe Influence of Melt Quality on the Formation of Fe Intermetallic in A360 Alloy(Polska Akad Nauk, Polish Acad Sciences, 2022) Bas, E. N.; Alper, S.; Tuncay, T.; Dispinar, D.; Kirtay, S.The solubility of Fe in aluminium alloys is known to be a problem in the casting of aluminium alloys. Due to the formation of various intermetallic phases, the mechanical properties decrease. Therefore, it is important to determine the formation mechanisms of such intermetallic. In this work, A360 alloy was used, and Fe additions were made. The alloy was cast into the sand and die moulds that consisted of three different thicknesses. In this way, the effect of the cooling rate was investigated. The holding time was selected to be 5 hours and every hour, a sample was collected from the melt for microstructural analysis. Additionally, the melt quality change was also examined by means of using a reduced pressure test where the bifilm index was measured. It was found that the iron content was increased after 2 hours of holding and the melt quality was decreased. There was a correlation between the duration and bifilm index. The size of AlSi-Mn-Fe phases was increased in parallel with the bifilm content regardless of the iron content.Öğe Investigation of Mechanical Properties of AA7075 Alloys Aged by Various Heat Treatments(Maik Nauka/Interperiodica/Springer, 2020) Sunar, T.; Tuncay, T.; Ozyurek, D.; Guru, M.In this study, annealing (O), artificial aging (T6), retro-regression aging (RRA) and high temperature pre-precipitation (HTPP) heat treatments were applied to AA7075 aluminium alloys. The effects of these treatments on the mechanical properties of AA7075 alloy were investigated. The microstructures of the samples were examined by Optical Microscope (OM), Scanning Electron Microscope (SEM) and Energy Dispersive X-ray (EDX) analysis. Then, X-ray diffraction analysis (XRD) was conducted to identify intermetallics formed in the microstructure of the samples. Tensile and hardness tests were carried out to investigate the mechanical properties. Results showed that secondary phase particles such as Al2Cu, Al2CuMg and MgZn2 are formed in the microstructures. In terms of the mechanical properties, T6 applied samples showed the best results. The HTPP applied alloy which presented optimum ductility behaviour among the other heat-treated samples. Dimples and some cleavage surfaces were observed on the fracture surfaces of the samples. Therefore, it is concluded that a ductile/semi-ductile fracture occurred on the samples.Öğe Investigation of Mechanical Properties of AA7075 Alloys Aged by Various Heat Treatments (vol 121, pg 1440, 2020)(Maik Nauka/Interperiodica/Springer, 2021) Sunar, T.; Tuncay, T.; Ozyurek, D.; Guru, M.[No abstract available]Öğe An Investigation of Sintering Characteristics of Reinforced with 15% TiB2 Titanium Composites(Natl Acad Sciences Ukraine, Inst Metal Physics, 2010) Ozyurek, D.; Tuncay, T.In this study, titanium matrix composite materials reinforced with 15% TiB2 were produced using mechanical alloying/milling (MA/MM) method. MA process carried out used an attritor. Titanium-composite powders were cold pressed at 630 MPa and then sintered at different temperatures for different time. Produced titanium-matrix composite (TMC) samples have been characterized by optical and scanning electron microscopy (SEM), X-ray diffraction (XRD), hardness, densification after sintering. The results showed that the amount of the reaction synthesized TiB increased with sintering temperature. However, transformation of the TiB2 ceramic particulates in the titanium matrix was not completed. The reinforced with 15 vol.% TiB2 titanium composite sintered at 1200 degrees C has maximum values of density and hardness.Öğe An investigation of sintering characteristics of reinforced with 15% TiB2 Titanium Composites(2010) Özyürek, D.; Tuncay, T.In this study, titanium matrix composite materials reinforced with 15% TiB2 were produced using mechanical alloying/milling (MA/MM) method. MA process carried out used an attritor. Titanium-composite powders were cold pressed at 630 MPa and then sintered at different temperatures for different time. Produced titanium-matrix composite (TMC) samples have been characterized by optical and scanning electron microscopy (SEM),X-ray diffraction (XRD), hardness, densification after sintering. The results showed that the amount of the reaction synthesized TiB increased with sintering temperature. However, transformation of the TiB2 ceramic particulates in the titanium matrix was not completed. The reinforced with 15 vol.% TiB2 titanium composite sintered at 1200°C has maximum values of density and hardness. © 2010.Öğe An Investigation of the Effects of Ageing Parameters on Wear Behaviours and Electrical Conductivity of Cu-Co-Be Alloys(Polish Acad Sciences Inst Physics, 2016) Ozyurek, D.; Yildirim, M.; Tuncay, T.In this study, the effects of ageing parameters were investigated on wear behaviours and electrical conductivity of Cu-Co-Be alloy. The samples were quenched at room temperature after solution heat treated for 1 h. Then, ageing processes were applied for three different temperatures (470 degrees C, 500 degrees C, 530 degrees C) and for three different ageing times (1, 2, 3 h). Microstructure examining, electrical conductivity and hardness measurements were carried out after ageing process. On the samples, which obtained the highest hardness values from hardness test (470 degrees C), there were carried out wear tests with 1 m s(-1) sliding speed under 30 N at four sliding distance (500-2000 m). Results clearly show that the highest hardness values were measured for samples aged at 470 degrees C for 3 h and hardness values were decreased with increasing ageing temperature. The lowest weight loss values were evaluated for samples aged at 470 degrees C for 3 h. The highest electrical conductivity values were measured at 500 degrees C for 1 h aged samples.Öğe Microstructure and mechanical properties of Sn-9Zn-xAl and Sn-9Zn-xCu lead-free solder alloys(Sciendo, 2020) Yavuzer, B.; Ozyurek, D.; Tuncay, T.This study investigates microstructures and mechanical properties of the alloys obtained by adding Cu (0.7 % and 0.9 %) and Al (0.7 % and 0.9 %) to lead-free Sn-9Zn eutectic soldering alloy produced by investment casting method. The results show that Cu5Zn8 phase has formed in the structure of Cu added alloys and the Al2O3 phase has formed due to addition of Al. It was found that small and round-shaped Al2O3 phase increased the tensile strength of the new alloy compared to the eutectic alloy. In addition, it was observed that the microhardness of Cu added alloys was lower than that of Sn-9Zn eutectic alloy, but the microhardness of alloys containing Al was higher compared to the other eutectic Sn-9Zn alloy.
