Yazar "Engin, S." seçeneğine göre listele

Listeleniyor 1 - 7 / 7
  • Küçük Resim Yok
    Öğe
    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.
  • Küçük Resim Yok
    Öğe
    Directionally Solidified Al-Cu-Si-Fe Quaternary Eutectic Alloys
    (Maik Nauka/Interperiodica/Springer, 2020) Buyuk, U.; Engin, S.; Kaya, H.; Cadirli, E.; Marasli, N.
    Directional solidification of eutectic alloys attracts considerable attention because of microhardness, tensile strength, and electrical resistivity affected by eutectic structures. In this research, solidification processing of Al-Cu-Si-Fe (Al-26 wt % Cu-6.5 wt % Si-0.5 wt % Fe) quaternary eutectic alloy by directional solidification is examined. The alloy was prepared by vacuum furnace and directionally solidified in Bridgman-type equipment. During the directional solidification process, the growth rates utilized varied from 8.25 to 164.80 mu m/s. The Al-Cu-Si-Fe system showed a eutectic transformation, which resulted in the matrix Al, lamellar Al2Cu, plate Si, and plate Al7Cu2Fe phases. The eutectic spacing lambda(Al2Cu) between lamellae of Al2Cu, as well as-lambda (Si), between plates of Si phase,-was measured. Additionally, the microhardness, tensile strength, and electrical resistivity of the studied alloy were determined using directionally solidified samples, and the experimental relationships between them were obtained. It was found that the microhardness, tensile strength, and electrical resistivity were affected by both eutectic spacing and the growth rate.
  • Küçük Resim Yok
    Öğe
    Experimental investigation of the effect of solidification processing parameters on the rod spacings in the Sn-1.2 wt.% Cu alloy
    (ELSEVIER SCIENCE SA, 2009) Cadirli, E.; Boyuk, U.; Engin, S.; Kaya, H.; Marasli, N.; Ulgen, A.
    Sn-1.2 wt.% Cu 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 = 2.69-8.88 K/mm) at a constant growth rate (V = 6.80 mu m/s) and with different growth rates (V = 2.78-136.36 mu m/s) at a constant temperature gradient (G = 2.69 K/mm) by using a Bridgman-type directional solidification apparatus. The microstructure of Sn-1.2 wt.% Cu alloy seems to be rod eutectic structure. The rod spacings (lambda) were measured from both transverse and longitudinal sections of the samples. The influence of the growth rate (V) and temperature gradient (G) on the rod spacings (lambda) and undercoolings (Delta T) was 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 results obtained in the present work have been compared with the similar experimental results obtained in the previous works for binary alloys. (C) 2009 Elsevier B.V. All rights reserved.
  • Küçük Resim Yok
    Öğe
    Investigation of microhardness and thermo-electrical properties in the Sn-Cu hypereutectic alloy
    (SPRINGER, 2010) Cadirli, E.; Boyuk, U.; Engin, S.; Kaya, H.; Marasli, N.; Ari, M.
    Sn-3 wt% Cu hypereutectic alloy was directionally solidified upward with different growth rates (2.24-133.33 mu m/s) at a constant temperature gradient (4.24 K/mm) and with different temperature gradients (4.24-8.09 K/mm) at a constant growth rate (7.64 mu m/s) in the Bridgman-type growth apparatus. The measurements of microhardness of directionally solidified samples were obtained by using a microhardness test device. The dependence of microhardness HV on the growth rate (V) and temperature gradient (G) were analyzed. According to these results, it has been found that with the increasing the values of V and G the value of HV increases. Variations of electrical resistivity (rho) and electrical conductivity (sigma) for casting samples with the temperature in the range of 300-500 K were also measured by using a standard dc four-point probe technique. The variation of Lorenz coefficient with the temperature for Sn-3 wt% Cu hypereutectic alloy was determined by using the measured values of electrical and thermal conductivities. The enthalpy of fusion for same alloy was determined by means of differential scanning calorimeter from heating trace during the transformation from eutectic liquid to eutectic solid.
  • Küçük Resim Yok
    Öğe
    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.
  • Küçük Resim Yok
    Öğe
    Measurements of Microhardness and Thermal and Electrical Properties of the Binary Zn-0.7wt.%Cu Hypoperitectic Alloy
    (SPRINGER, 2010) Kaya, H.; Boyuk, U.; Engin, S.; Cadirli, E.; Marasli, N.
    Zn-0.7wt.%Cu hypoperitectic alloys were directionally solidified upwards with different temperature gradients (3.85 K/mm to 9.95 K/mm) at a constant growth rate (0.042 mm/s), and with different growth rates (0.0083 mm/s to 0.436 mm/s) at a constant temperature gradient (3.85 K/mm), using a Bridgman-type growth apparatus. Measurements of microhardness of the directionally solidified samples were carried out. The dependence of micro- hardness (HV) on growth rate (V) and temperature gradient (G) was analyzed. According to these results, it has been found that, for increasing values of G and V, the value of HV increases. Variations of electrical resistivity (rho) and electrical conductivity (sigma) for cast samples with temperature from 300 K to 670 K were also measured by using a standard direct-current (DC) four-point probe technique. The variation of the Lorenz coefficient with temperature for the Zn-0.7wt.%Cu hypoperitectic alloy was determined using the measured values of electrical conductivity and thermal conductivity. The enthalpy of fusion for the same alloy was determined by means of differential scanning calorimetry (DSC) from the heating trace during the transformation from liquid to solid.
  • Küçük Resim Yok
    Öğe
    Variations of microhardness with the solidification processing parameters and thermo-electrical properties with the temperature in the Sn-Cu alloy
    (REDAKCIA KOVOVE MATERIALY, 2009) Cadirli, E.; Boyuk, U.; Engin, S.; Kaya, H.; Marasli, N.
    Sn-1.2wt.%Cu eutectic alloy was directionally solidified upward with different growth rates (2-78-136.36 mu m s(-1)) at a constant temperature gradient (2.69 K mm(-1)) and with different temperature gradients (2.69-8.88 K mm(-1)) at a constant growth rate (6.80 mu m s(-1)) in the Bridgman-type growth apparatus. The measurements of microhardness of directionally solidified samples were obtained by using a microhardness test device. The dependence of microhardness HV on the growth rate (V) and temperature gradient (G) were analysed. According to these results, it has been found that with the increasing values of V and G, the values of HV increase. Variations of electrical resistivity (p) and electrical conductivity (a) for Sn-1.2wt.%Cu cast alloy with the temperature in the range of 300-500 K were also measured by using a standard d.c. four-point probe technique. The variation of Lorenz coefficient with the temperature for Sn-1.2wt.%Cu eutectic alloy was determined by using the measured values of electrical conductivity and thermal conductivity. The enthalpy of fusion for the same alloy was determined by means of differential scanning calorimeter (DSC) from heating trace during the transformation from eutectic liquid to eutectic solid.