Yazar "Keslioglu, K." seçeneğine göre listele

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    A study of microstructure and solidification behaviour of Zn-Cu alloy
    (REDAKCIA KOVOVE MATERIALY, 2010) Boyuk, U.; Engin, S.; Kaya, H.; Cadirli, E.; Marasli, N.; Keslioglu, K.
    Zn-1.5wt.%Cu peritectic alloy was prepared in a graphite crucible under a vacuum atmosphere. Unidirectional solidification of Zn-1.5wt.%Cu peritectic alloy was carried out with the Bridgman method by using metals of 99.99 % purity under the argon atmosphere and two different conditions; with a temperature gradient (G) range of 1.99-7.81 K mm(-1) at constant growth rate (V) and a growth rate range of 8.41-661.11 mu m s(-1) at a constant temperature gradient. The microstructures of the directionally solidified Zn-1.5wt.%Cu peritectic samples were observed to be cellular. From both transverse and longitudinal sections of the samples, cellular spacing (lambda), and cell tip radius (R) were measured and expressed as functions of solidification processing parameters (G and V) using a linear regression analysis. The experimental results were also compared with values calculated according to the current theoretical and numerical models, and similar previous experimental results.
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    Dependency of Microstructural Parameters and Microindentation Hardness on the Temperature Gradient in the In-Bi-Sn Ternary Alloy with a Low Melting Point
    (KOREAN INST METALS MATERIALS, 2008) Kaya, H.; Boyuk, U.; Cadirli, E.; Ocak, Y.; Akbulut, S.; Keslioglu, K.; Marasli, N.
    The ternary alloy In-21.5 at.% Bi-17.8 at.% Sn, which has a melting point of 60 degrees C, was directionally solidified upward with a constant growth rate (V = 3.2 mu m/s) and different temperature gradients (G = 0.91 K/mm to 2.85 K/mm) by using a Bridgman-type directional solidification furnace. The lamellar spacings (lambda) and microhardness (H(v)) were measured from both the transverse and longitudinal sections of the samples. The dependence of the lamellar spacings (lambda) and microhardness (H(v)) on the temperature gradients (G) were determined by means of linear regression analysis. According to these results, the value of lambda decreases as the value of G increases and the value of Hv increases for a constant V. The results obtained in this work are compared with previous similar experimental results obtained for binary or ternary alloys.
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    Determination of Interfacial Energies for Solid Al Solution in Equilibrium with Al-Cu-Ag Liquid
    (KOREAN INST METALS MATERIALS, 2010) Keslioglu, K.; Ocak, Y.; Aksoz, S.; Marasli, N.; Cadirli, E.; Kaya, H.
    The equilibrated grain boundary groove shapes of a solid Al solution in equilibrium with Al-Cu-Ag liquid were observed from a quenched sample using a radial heat flow apparatus. The Gibbs-Thomson coefficient, solid-liquid interfacial energy, and grain boundary energy of the solid Al solution were determined from the observed grain boundary groove shapes. The thermal conductivity of the solid phase for Al-16.42 at.% Ag-4.97 at.% Cu and Al-16.57 at.% Ag-11.87 at.% Cu alloys and the thermal conductivity ratio of the liquid phase to the solid phase for Al-16.57 at.% Ag-11.87 at.% Cu alloy at the melting temperature were also measured with a radial heat flow apparatus and a Bridgman-type growth apparatus, respectively.
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    Determination of interfacial energies of solid Sn solution in the In-Bi-Sn ternary alloy
    (ELSEVIER SCIENCE INC, 2009) Akbulut, S.; Ocak, Y.; Marasli, N.; Keslioglu, K.; Kaya, H.; Cadirli, E.
    The equilibrated grain boundary groove shapes of solid Sn solution (Sn-40.14 at.% In-16.11 at.% Bi) in equilibrium with the In-Bi-Sn liquid (In-21.23 at.% Bi-19.04 at.% Sn) were observed from the quenched sample at 59 degrees C. Gibbs-Thomson coefficient, solid-liquid interfacial energy and grain boundary energy of the solid Sn solution have been determined from the observed grain boundary groove shapes. The thermal conductivity of solid phase for In-21.23 at.% Bi-19.04 at.% Sn alloy and the thermal conductivity ratio of liquid phase to solid phase at the melting temperature have also been measured with radial heat flow apparatus and Bridgman type growth apparatus, respectively. (C) 2008 Elsevier Inc. All rights reserved.
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    Determination of solid-liquid interfacial energies in the In-Bi-Sn ternary alloy
    (IOP PUBLISHING LTD, 2008) Akbulut, S.; Ocak, Y.; Marasli, N.; Keslioglu, K.; Kaya, H.; Cadirli, E.
    The equilibrated grain boundary groove shapes of solid In(2)Bi solution in equilibrium with the In-Bi-Sn eutectic liquid were observed from a quenched sample at 59 degrees C. The Gibbs-Thomson coefficient, solid-liquid interfacial energy and grain boundary energy of the solid In2Bi solution have been determined to be (1.42 +/- 0.07) x 10(-7) Km, (49.6 +/- 5.0) x 10(-3) Jm(-2) and (97.1 +/- 10.7) x 10(-3) Jm(-2), respectively, from the observed grain boundary groove shapes. The thermal conductivities of the solid phases for In-21.23 at% Bi-19.04 at% Sn and In-30.5 at% Bi-3 at% Sn alloys and the thermal conductivity ratio of the liquid phase to the solid phase for In-21.23 at% Bi-19.04 at% Sn have also been measured with a radial heat flow apparatus and a Bridgman type growth apparatus, respectively, at their melting temperature.
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    Directional solidification of Al-Cu-Ag alloy
    (SPRINGER HEIDELBERG, 2009) Boyuk, U.; Marasli, N.; Kaya, H.; Cadirli, E.; Keslioglu, K.
    Al-Cu-Ag alloy was prepared in a graphite crucible under a vacuum atmosphere. The samples were directionally solidified upwards under an argon atmosphere with different temperature gradients (G=3.99-8.79 K/mm), at a constant growth rate (V=8.30 mu m/s), and with different growth rates (V=1.83-498.25 mu m/s), at a constant gradient (G=8.79 K/mm) by using the Bridgman type directional solidification apparatus. The microstructure of Al-12.80-at.%-Cu-18.10-at.%-Ag alloy seems to be two fibrous and one lamellar structure. The interlamellar spacings (lambda) were measured from transverse sections of the samples. The dependence of interlamellar spacings (lambda) on the temperature gradient (G) and the growth rate (V) were determined by using linear regression analysis. According to these results it has been found that the value of lambda decreases with the increase of values of G and V. The values of lambda (2) V were also determined by using the measured values of lambda and V. The experimental results were compared with two-phase growth from binary and ternary eutectic liquid.
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    Effect of solidification processing parameters on the cellular spacings in the Al-0.1 wt% Ti and Al-0.5 wt% Ti alloys
    (ELSEVIER SCIENCE SA, 2007) Gunduz, M.; Kaya, H.; Cadirli, E.; Marasli, N.; Keslioglu, K.; Saatci, B.
    The aim of this work is to investigate the relationship between solidification processing parameters (temperature gradient, G, growth rate, V, and cooling rate T), and cellular spacing, lambda, in the Al-0.1 wt% Ti and Al-0.5 wt% Ti alloys grown at high growth rates. In order to achieve this aim, the specimens were solidified under argon atmosphere and steady-state conditions upward with different temperature gradients, G at a constant growth rate, V and with different V at a constant G for the Al-Ti alloys in the Bridgman type directional solidification apparatus. The cellular spacing,. was measured and expressed as functions of solidification processing parameters, G, V and T by using a linear regression analysis. The results were compared with similar previous experimental work and current theoretical models suggested for cellular growth. (c) 2006 Elsevier B.V. All rights reserved.
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    Effects of growth rate and temperature gradient on the microstructure parameters in the directionally solidified succinonitrile-7.5 wt.% carbon tetrabromide alloy
    (ELSEVIER SCIENCE SA, 2008) Marasli, N.; Keslioglu, K.; Arslan, B.; Kaya, H.; Cadirli, E.
    Succinonitrile (SCN)-7.5 wt.% carbon tetrabromide (CTB) alloy was unidirectionally solidified with a constant growth rate (V = 33 mu m/s) at five different temperature gradients (G = 4.1-7.6 K/mm) and with a constant temperature gradient (G = 7.6 K/mm) at five different growth rates (V = 7.2-116.7 mu m/s). The primary dendrite arm spacings, secondary dendrite arm spacings, dendrite tip radius and mushy zone depths were measured. Theoretical models for the microstructure parameters have been compared with the experimental observations, and a comparison of our results with the current theoretical models and previous experimental results have also been made. (C) 2007 Elsevier B.V. All rights reserved.
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    Experimental determination of interfacial energies for Ag2Al solid solution in the CuAl2-Ag2Al system
    (IOP PUBLISHING LTD, 2009) Ocak, Y.; Akbulut, S.; Keslioglu, K.; Marasli, N.; Cadirli, E.; Kaya, H.
    The equilibrated grain boundary groove shapes of solid solution Ag2Al in equilibrium with an Al-Cu-Ag liquid were observed from a quenched sample with a radial heat flow apparatus. The Gibbs-Thomson coefficient, solid-liquid interfacial energy and grain boundary energy of the solid solution Ag2Al have been determined from the observed grain boundary groove shapes. The thermal conductivity of the solid phase and the thermal conductivity ratio of the liquid phase to solid phase for Ag2Al-28.3 at the % CuAl2 alloy at the melting temperature have also been measured with a radial heat flow apparatus and Bridgman type growth apparatus, separately.
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    Experimental determination of solid-solid and solid-liquid interfacial energies of solid epsilon (CuZn5) in the Zn-Cu alloy
    (ELSEVIER SCIENCE SA, 2009) Kaygisiz, Y.; Akbulut, S.; Ocak, Y.; Keslioglu, K.; Marasli, N.; Cadirli, E.; Kaya, H.
    The equilibrated grain boundary groove shapes of solid epsilon; (CuZn5) in equilibrium with Zn-1.75 at.% Cu peritectic liquid and solid epsilon (CuZn5) in equilibrium with solid Zn solution (Zn-2.83 at.% Cu) were observed from a quenched sample. The Gibbs-Thomson coefficient, solid-liquid interfacial energy and grain boundary energy of solid epsilon (CuZn5) in equilibrium with Zn-1.75 at.% Cu peritectic liquid have been determined to be (4.9 +/- 0.3) x 10(-8) K m, (76.0 +/- 9.1) x 10(-3) J m(-2) and (150.3 +/- 19.5) x 10(-3) J m(-2), respectively. For the first time, the equilibrated grain boundary groove shapes of solid epsilon (CuZn5) in equilibrium with solid Zn solution have been observed. The Gibbs-Thomson coefficient, solid-solid interfacial energy and grain boundary energy of solid epsilon (CuZn5) in equilibrium with solid Zn have also been determined to be (4.7 +/- 0.3) x 10(-8) K m, (72.9 +/- 8.7) x 10(-3) J m(-2) and (144.1 +/- 18.7) x 10(-3) J m(-2), respectively from the observed grain boundary groove shapes. The thermal conductivities of solid Zn solution and solid epsilon; (CuZn5) phase (Zn-12 at.% Cu) have been measured with radial heat flow apparatus. The thermal conductivity ratios of the equilibrated liquid phase to solid phase for Zn-1.75 at.% Cu and Zn-12 at.% Cu alloys have also been measured with Bridgman type growth apparatus. (C) 2009 Elsevier B.V. All rights reserved.
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    Interfacial energies of solid CuAl2 in the CuAl2-Ag2Al pseudo binary alloy
    (ELSEVIER SCIENCE SA, 2010) Ocak, Y.; Aksoz, S.; Keslioglu, K.; Marasli, N.; Cadirli, E.; Kaya, H.
    Gibbs-Thomson coefficient, solid-liquid interfacial energy and grain boundary energy are important parameters for people doing comparisons between experimentally observed solidification morphology and predictions from theoretical models. Thus the Gibbs-Thomson coefficient, solid-liquid interfacial energy and grain boundary energy of solid CuAl2 in the CuAl2-Ag2Al pseudo binary system have been determined from observed grain boundary groove shapes. The variation of thermal conductivity of solid CuAl2 with temperature has also been measured by using a radial heat flow apparatus. (C) 2010 Elsevier By. All rights reserved.
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    Interfacial energy of solid In2Bi intermetallic phase in equilibrium with In-Bi eutectic liquid at 72 degrees C equilibrating temperature
    (ELSEVIER SCIENCE INC, 2008) Akbulut, S.; Ocak, Y.; Marasli, N.; Keslioglu, K.; Boeyuek, U.; Cadirli, E.; Kaya, H.
    A radial temperature gradient on the sample was established by heating from centre with a single heating wire and cooling the outside of sample at -10 degrees C with a heating/refrigerating circulating bath containing an aqueous ethylene glycol solution. The equilibrated grain boundary groove shapes of solid In2Bi (In-33.2 at.% Bi) in equilibrium with In-Bi eutectic liquid (In-22 at.% Bi) were observed from quenched sample at 72 degrees C. Gibbs-Thomson coefficient and solid-liquid interfacial energy of solid In2Bi in equilibrium with In-Bi eutectic liquid have been determined to be (11.3 +/- 0.6) x 10(-8) K m and (47.8 +/- 4.8) x 10(-3) J m(-2) from the observed grain boundary groove shapes. The grain boundary energy of solid In2Bi phase has been calculated to be (92.8 +/- 10.2) x 10(-3) J m(-2) by considering a force balance at the grain boundary grooves. The thermal conductivities of solid In solution (In-12.4 at.% Bi), solid In2Bi (In-33.2 at.% Bi), the eutectic liquid phase (In-22 at.% Bi) and their ratio at 72 degrees C have also been measured with radial heat flow apparatus and Bridgman type growth apparatus. (C) 2007 Elsevier Inc. All rights reserved.
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    Investigation of the effect of solidification processing parameters on the rod spacings and variation of microhardness with the rod spacing in the Sn-Cu hypereutectic alloy
    (SPRINGER, 2010) Cadirli, E.; Boyuk, U.; Engin, S.; Kaya, H.; Marasli, N.; Keslioglu, K.; Ulgen, A.
    Sn-3 wt% Cu hypereutectic alloy was prepared in a graphite crucible under the vacuum atmosphere. The samples were directionally solidified upwards under argon atmosphere with different temperature gradients (G = 4.24-8.09 K/mm) at a constant growth rate (V = 7.64 mu m/s) and with different growth rates (V = 2.24-133.33 mu m/s) at a constant temperature gradient (G = 4.24 K/mm) by using a Bridgman type directional solidification apparatus. The microstructure of directional solidified Sn-3 wt% Cu alloy seems to be rod eutectic structure. The influence of the growth rate (V) and temperature gradient (G) on the rod spacing (lambda) and undercooling (Delta T) were analysed. The values of lambda(2)V, lambda(2)G, Delta T lambda, Delta TV(-0.5) and Delta TG(-0.5) were determined by using the Jackson-Hunt eutectic theory. The dependence of microhardness (HV) on the rod spacing (lambda) was analyzed. According to present results, it has been found that the value of HV increases with the increasing the value of lambda.
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    Measurement of solid-liquid interfacial energy in the In-Bi eutectic alloy at low melting temperature
    (IOP PUBLISHING LTD, 2007) Marasli, N.; Akbulut, S.; Ocak, Y.; Keslioglu, K.; Boeyuek, U.; Kaya, H.; Cadirli, E.
    The Gibbs-Thomson coefficient and solid-liquid interfacial energy of the solid In solution in equilibrium with In Bi eutectic liquid have been determined to be (1.46 +/- 0.07) x 10(-7) K m and (40.4 +/- 4.0) x 10(-3) J m(-2) by observing the equilibrated grain boundary groove shapes. The grain boundary energy of the solid In solution phase has been calculated to be (79.0 +/- 8.7) x 10(-3) J m(-2) by considering force balance at the grain boundary grooves. The thermal conductivities of the In-12.4 at.% Bi eutectic liquid phase and the solid In solution phase and their ratio at the eutectic melting temperature (72 degrees C) have also been measured with radial heat flow apparatus and Bridgman-type growth apparatus.
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    The effect of growth rate on microstructure and microindentation hardness in the In-Bi-Sn ternary alloy at low melting point
    (ELSEVIER SCIENCE SA, 2009) Cadirli, E.; Boyuk, U.; Kaya, H.; Marasli, N.; Keslioglu, K.; Akbulut, S.; Ocak, Y.
    In-21.5 at.% Bi-17.8 at.% Sn ternary alloy which has 333 K melting point was directionally solidified upward with a constant temperature gradient (G = 0.91 K/mm) in a wide range of growth rates (3.2-157.1 mu m/s) with a Bridgman type directional solidification furnace. The lamellar spacings (lambda) and microhardness values (H-V) were measured from both transverse and longitudinal sections of the samples. The dependence of lamellar spacings (lambda) and microhardness (H-V) on the growth rate (V) was determined by using linear regression analysis. According to these results, it has been found that the value of lambda decreases with the increasing value of V and whereas, the value of H-V increases for a constant G. The values of lambda V-2 were determined by using the measured values of lambda and V. The results obtained in this work have been compared with the previous similar experimental results obtained for binary or ternary alloys. (C) 2008 Elsevier B.V. All rights reserved.
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    Thermal conductivity and interfacial energies of solid Sn in the Sn-Cu alloy
    (ELSEVIER SCIENCE BV, 2010) Kaygisiz, Y.; Ocak, Y.; Aksoz, S.; Marasli, N.; Keslioglu, K.; Cadirli, E.; Kaya, H.
    The equilibrated grain boundary groove shapes of solid Sn in equilibrium with the Sn-Cu eutectic liquid were observed from a quenched sample. The Gibbs-Thomson coefficient, solid-liquid interfacial energy and grain boundary energy of solid Sn have been determined to be (8.7 +/- 0.6) x 10(-8) Km, (113.1 +/- 13.6) x 10(-3) J m(-2) and (222.4 +/- 28.9) x 10(-3) J m(-2), respectively. The thermal conductivity of solid phase and the thermal conductivity ratio of liquid phase to solid phase for Sn-1.3 at.%Cu alloy have also been measured with radial heat flow apparatus and Bridgman type growth apparatus, respectively. (C) 2009 Elsevier B. V. All rights reserved.
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    Variations of microhardness with solidification parameters and electrical resistivity with temperature for Al-Cu-Ag eutectic alloy
    (ELSEVIER SCIENCE BV, 2012) Boyuk, U.; Marasli, N.; Cadirli, E.; Kaya, H.; Keslioglu, K.
    Al-Cu-Ag eutectic alloy was directionally solidified upwards with different growth rates (1.83-498.25 mu m/s) at a constant temperature gradient (8.79 K/mm) and with different temperature gradients (3.99-8.79 K/mm) at a constant growth rate (8.30 mu m/s) by using a Bridgman type directional solidification apparatus. The dependence of microhardness (HV) on the growth rate (V), temperature gradient (G) and microstructure parameter (lambda) were found to be HV = k(1) V(0.10), HV = k(2) G(0.13) and HV = k(3) lambda(-0.22), respectively. The electrical resistivity of the Al-Cu-Ag eutectic cast alloy increases linearly with the temperature in the range of 300-780 K. The enthalpy of fusion and specific heat change during melting for same alloy were also determined to be 223.8 J/g, and 0.433 J/g K, respectively by a differential scanning calorimeter from heating curve during the transformation from eutectic solid to eutectic liquid. (C) 2011 Elsevier B. V. All rights reserved.