Yazar "Kolukisa, Sedat" seçeneğine göre listele

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    Application of ANN in the prediction of the pore concentration of aluminum metal foams manufactured by powder metallurgy methods
    (Springer London Ltd, 2008) Ozan, Sermin; Taskin, Mustafa; Kolukisa, Sedat; Ozerdem, Mehmet Sirac
    In this work, the effect of fabrication parameters on the pore concentration of aluminum metal foam, manufactured by the powder metallurgy process, has been studied. The artificial neural network (ANN) technique has been used to predict pore concentration as a function of some key fabrication parameters. Aluminum metal foam specimens were fabricated from a mixture of aluminum powders (mean particle size 60 mu m) and NaCl at 10, 20, 30, 40(wt)% content under a pressure of 200, 250, and 300 MPa. All specimens were then sintered at 630 degrees C for 2.5 h in argon atmosphere. For pore formation (foaming), sintered specimens were immersed into 70 degrees C hot running water. Finally, the pore concentration of specimens was recorded to analyze the effect of fabrication parameters (namely, NaCl ratio, NaCl particle size, and compacting pressure) on the foaming behavior of compacted specimens. It has been recorded that the above-mentioned fabrication parameters are effective on pore concentration profile while pore diameters remain unchanged. In the ANN training module, NaCl content (wt)%, NaCl particle size (mu m), and compacting pressure (MPA) were employed as inputs, while pore concentration % (volume) of compacts related to fabrication parameters was employed as output. The ANN program was successfully used to predict the pore concentration % (volume) of compacts related to fabrication parameters.
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    Artificial Neural Network approach to predict mechanical properties of hot rolled, nonresulfurized, AISI 10xx series carbon steel bars
    (Elsevier Science Sa, 2008) Ozerdem, Mehmet Sirac; Kolukisa, Sedat
    In this study, Artificial Neural Network approach to predict mechanical properties of, hot rolled, nonresulfurized, AISI 10xx series carbon steel bars were obtained using a back-propagation neural network that uses gradient descent learning algorithm. In Artificial Neural Network training module, C%, Si%, Mn% contents were employed as input and tensile strength, yield strength, elongation, reduction in area, hardness were used as outputs. ANN system was trained using the prepared training set (also known as learning set). After training process, the test data were used to check system accuracy. As a result the neural network was found successful for the prediction of mechanical properties of, hot rolled, nonresulfurized, AISI 10xx series carbon steels under given conditions. (C) 2007 Elsevier B.V. All rights reserved.
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    Artificial neural network approach to predict the mechanical properties of Cu-Sn-Pb-Zn-Ni cast alloys
    (Elsevier Sci Ltd, 2009) Ozerdem, Mehmet Sirac; Kolukisa, Sedat
    In this study, an artificial neural network approach is employed to predict the mechanical properties of Cu-Sn-Pb-Zn-Ni cast alloys. In artificial neural network (ANN), multi layer perceptron (MLP) architecture with back-propagation algorithm is utilized. In Artificial Neural Network training module, Cu-Sn-Pb-Zn-Ni (wt%) contents were employed as input while yield strength, tensile strength and elongation were employed as outputs. ANN system was trained using the prepared training set (also known as learning set). After training process, the test data were used to check system accuracy, As a result of the study neural network was found successful for the prediction of yield strength, tensile strength and elongation of Cu-Sn-Pb-Zn-Ni alloys. (C) 2008 Elsevier Ltd. All rights reserved.
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    The effect of the process temperature on the bondability in diffusion bonding of AISI 430 with nodular cast iron
    (Carl Hanser Verlag, 2006) Taskin, Mustafa; Ozan, Sermin; Kolukisa, Sedat
    The effect of process temperature on the bondability of stainless steel AISI 430 and nodular cast iron was studied. The diffusion bonding was investigated experimentally under a protective atmosphere at various temperatures and a prescribed constant pressure blow which would cause macro-deformation. Microstructure examinations were carried out with the help of optical microscopy, SEM and EDS. Hardness values were measured by HV scale under a load of 200 g. At the bond interface cross section, decarburized and dechromised regions were observed on the ductile cast iron side and the stainless steel side respectively. Best mechanical and metallurgical properties were observed for the specimen bonded at 1100 degrees C process temperature at 15 MPa, for 20 min. As a function of the process temperature elevation, an increase of graphite atoms, migrating towards the interface, and a reduction of graphite atoms at the nodular graphite diameters was noticed.
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    The effect of the process temperature on the bondability in transient liquid phase (tlp) diffusion bonding of AISI 430 ferritic stainless steel with nodular (spheroid) cast iron using a copper interlayer
    (Carl Hanser Verlag, 2006) Ozan, Sermin; Taskin, Mustafa; Kolukisa, Sedat
    The effect of the process temperature on the bondability in the transient liquid phase (tlp) was studied. The diffusion bonding of AISI 430 with nodular cast iron using a copper interlayer was investigated experimentally under a protective atmosphere at various temperatures and at a defined constant blow pressure which would cause macro deformation. Microstructure examinations were carried out with the help of optical microscopy, SEM and EDS. Hardness values were measured by HV scale under a load of 150 g. At the bond interface, decarburized and dechromised regions were observed on the ductile cast iron side and stainless steel side respectively. Best mechanical and metallurgical properties were observed for the specimen bonded at 1100 degrees C for 20 min. As a function of an elevation of the process temperature, an increase in the amount of graphite atoms that migrated toward the interface and a reduction at the nodular graphite diameters was noticed.
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    The effect of the welding temperature on the weldability in diffusion welding of martensitic (AISI 420) stainless steel, with ductile (spheroidal graphite-nodular) cast iron
    (Elsevier Science Sa, 2007) Kolukisa, Sedat
    In this study, the effect of welding temperature on the weldability in diffusion welding of martensitic (AISI 420), stainless steel with ductile (spheroidal graphite-nodular) cast iron was investigated experimentally under protective atmosphere at various temperatures and constant prescribed pressure blow those which would cause macrodeformation. Microstructure examinations were carried out by SEM and EDS. Hardness values were measured by Hv scale under a load of 200 g along the weld interface, mutual chrome and carbon diffusion were observed on ductile cast iron side and stainless steel side, respectively. On the other hand, as a function of process temperature elevation, increase in the amount carbon and chrome atoms migrated toward to interface, reduction at nodular graphite diameters was also noticed. As a result of all evaluations and tests carried out, it can be said that, best gathered mechanical and metallurgical properties were observed at the specimen bonded at 1100 degrees C process temperature at 12 MPa, for 20 min. (c) 2006 Elsevier B.V. All rights reserved.
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    The Effect of Welding Speed on the Laser Welding of AISI 430 Ferritic Stainless-AISI 1010 Low-Carbon Steel
    (Carl Hanser Verlag, 2009) Taskin, Mustafa; Caligulu, Ugur; Kolukisa, Sedat
    In this study, the effect of welding speed on the laser welding of AISI 430 ferritic stainless steel with AISI 1010 low-carbon steels was investigated. Laser welding experiments, were carried out under argon atmosphere, 2000 W constant welding power and 100, 200,300 cm/min welding speeds. The microstructures of the welded joints were examined by optical microscopy and SEM analysis. The tensile strength of the welded joints was measured. The result of all observations, tests and measurements indicated that the best properties were observed at the specimens welded at 100 cm/min welding speed.
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    Mechanical Properties of Ferrochrome Based Hardfacing Layers Coated on AISI 1020 Steel Obtained by the Aid of Plasma Transfer Arc (PTA) Process
    (Carl Hanser Verlag, 2010) Cay, Vedat Veil; Ozan, Sermin; Topuz, Polat; Kolukisa, Sedat
    Mechanical properties of ferrochrome based hardfacing layers coated on AISI 1020 steel obtained by the aid of Plasma Transfer Arc (PTA) was experimentally studied. Ferrochrome powders were mixed with sodium silicate gel to avoid spreading. The mixture was laid to 1.5 x 8 x 100 mm slots machined on AISI 1020 steel. Hardfacing layer was performed by PTA process under pure Argon as protective gas with 130 A/20 V power supply. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), micro hardness and abrasive tests were employed for the evaluation of ferrochrome alloyed coating. Hardfacing was successfully performed under given conditions. Microstructural changes and formations (phases) significantly improved hardness, abrasive wear resistance and integrity of hardfacing layer.
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    Transient liquid phase (tlp) diffusion bonding of Ti45Ni49Cu6 P/M components using Cu interlayer
    (Springer London Ltd, 2009) Kejanli, Haluk; Taskin, Mustafa; Kolukisa, Sedat; Topuz, Polat
    In this study, transient liquid phase diffusion bonding parameters of Ti45Ni49Cu6 P/M components using copper interlayer were experimentally investigated in a protective (argon) atmosphere. Bonding processes of sintered Ti45Ni49Cu6 P/M compacts were carried out at various temperatures and bonding periods while bonding pressure was kept unchanged. The process pressure, 20 MPa, was selected just below those which would cause macro deformations. Optical microscopy, scanning electron microscopy, and energy dispersive spectroscopy were employed for microstructure examinations. Shear strength and hardness (HB) of bonded specimens were measured at bond interface and parent materials for mechanical property evaluations. Along the bond interface, copper, titanium, and nickel atom mutual migration was observed. Structural tests, metallographic analysis have shown the integrity of the diffusion bonded hardware, bonded between 940 and 970A degrees C process temperatures, for 40-60-min bonding periods.