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Öğe Directional solidification of Al-Cu-Si-Mg quaternary eutectic alloy(Elsevier Science Sa, 2017) Kaygisiz, Yusuf; Marasli, NecmettinThe effects of growth rates on the microstructure, microhardness, tensile strength, and electrical resistivity were studied in directionally solidified Al-Cu -Si -Mg (A1-28 wt%Cu-6wt.%Si-2.2 wt%Mg) quaternary eutectic alloy. The directional solidification process was carried out at five different growth rates (V = 9.63-173.5 mu m/s) at a constant temperature gradient (G = 6.88 Kimm). The microstructure of the directionally solidified Al-Cu-Si-Mg quaternary eutectic alloy consists of Al solid solution, irregular Si plates, and intermetallic Al2Cu (theta) and Cu2Mg8Si6Al5 (Q) phases with honeycomb morphology. The dependencies of lamellar spacing, microhardness, tensile strength, and electrical resistivity on growth rates were found to be lambda(CuAl2) = 19.05 V-041, lambda(Cu2Mg8Si6Al5) = 51.28 V-0.43, lambda(si) = 8.74 V-0.46, HV = 170.7 + 79.08V(0.25), HV = 237.68(V)(0.043) sigma = 343.45(V)(0.15), and rho = 3.42 x 10(-8)(V)(0.10) orespectively, for the Al-Cu-Si-Mg quaternary eutectic alloy. The bulk growth rates were also determined lambda(2)(si) V = 92.24, lambda(2)(CuAl2) = 669.2, and lambda(Cu2Mg8Si6Al5) V = 4205.5 mu(3)/s by using the measured values of lambda Mg2Si, lambda(CuAl2), lambda(Cu2Mg8Si6Al5), and V for the Si plates and intermetallic Al2Cu (theta) and Cu2Mg8Si6Al5 (Q) phases in the Al-Cu-Si-Mg eutectic alloy, respectively. (C) 2017 Elsevier B.V. All rights reserved.Öğe Hardness and Electrical Resistivity of Al-13 wt % Mg2Si Pseudoeutectic Alloy(Pleiades Publishing Inc, 2017) Kaygisiz, Yusuf; Marasli, NecmettinIn the present work, effect of growth rates on microhardness, electrical properties and microstructure for directionally solidified Al-13 wt % Mg2Si pseudoeutectic alloy at a constant temperature gradient were studied. Directional solidification process were carried out with five different growth rates (V = 8.33-175.0 mu m/s) at a constant temperature gradient (G = 6.68 K/mm) by using a Bridgman type directional solidification furnace. Microstructure of directionally solidified Al-13 wt % Mg2Si pseudoeutectic alloy was observed as Mg2Si coral-like structure phase dispersed into primary alpha-Al phase matrix. The electrical resistivity for Al-13 wt % Mg2Si pseudoeutectic alloy, were measured by the d. c. four-point probe method. The dependency of microhardness and electrical resistivity on growth rates were obtained as IIV = 135.7 (V)(0.09) and rho = 17.30 x 10(-8)(V)(0.08) respectively for Al-Mg2Si pseudoeutectic alloy. The results obtained in present work were compared with the previous similar experimental results.Öğe The measurements of electrical and thermal conductivity variations with temperature and phonon component of the thermal conductivity in Sn-Cd-Sb, Sn-In-Cu, Sn-Ag-Bi and Sn-Bi-Zn alloys(Elsevier France-Editions Scientifiques Medicales Elsevier, 2016) Altintas, Yemliha; Kaygisiz, Yusuf; Ozturk, Esra; Aksoz, Sezen; Keslioglu, Kazim; Marasli, NecmettinThe electrical and thermal conductivity variations with temperature for lead-free ternary solders, namely Sn-41.39 at.% Cd-6.69 at.% Sb, Sn-49 at.% In-1 at.% Cu, Sn-50 at.% Ag-10 at.% Bi and Sn-32 at.% Bi-3 at.% Zn alloys, were measured by the d.c. four-point probe method and radial heat flow apparatus, respectively. The contributions of electrons and phonons to the thermal conductivity were separately determined by using the measured values of the thermal and electrical conductivities obtained by the Wiedemann-Franz law in the lead-free ternary solders. The percentages of the phonon component of thermal conductivity were found to be in the range of 46-55%, 46-50%, 38-47% and 69-73% for Sn-41.39 at.% Cd-6.69 at.% SU, Sn-49 at.% In-1 at.% Cu, Sn-50 at.% Ag-10 at.% Bi and Sn-32 at.% Bi-3 at.% Zn alloys at the ranges of 318-443 K temperature, respectively. The temperature coefficients (alpha) of electrical conductivity for the lead-free ternary solders were found to be 2.47 x 10(-3), 4.97 x 10(-3), 1.14 x 10(-3) and 1.00 x 10(-3) K-1, respectively. The thermal conductivities of the solid phases at their melting temperature and the thermal temperature coefficients for the lead-free ternary solders were also found to be 47.72 +/- 2.38, 68.57 +/- 3.42, 73.52 +/- 3.67, 37.53 +/- 1.87 W/Km and 1.47 x 10(-3), 1.48 x 10(-3), 1.85 x 10(-3) and 2.21 x 10(-3) K-1, respectively. (C) 2015 Elsevier Masson SAS. All rights reserved.Öğe Microstructural, mechanical, and electrical characterization of directionally solidified Al-Cu-Mg eutectic alloy(Maik Nauka/Interperiodica/Springer, 2017) Kaygisiz, Yusuf; Marasli, NecmettinThe composition of an Al-Cu-Mg ternary eutectic alloy was chosen to be Al-30 wt% Cu-6 wt % Mg to have the Al2Cu and Al2CuMg solid phases within an aluminum matrix (alpha-Al) after its solidification from the melt. The alloy Al-30 wt % Cu-6 wt % Mg was directionally solidified at a constant temperature gradient (G = 8.55 K/mm) with different growth rates V, from 9.43 to 173.3 mu m/s, by using a Bridgman-type furnace. The lamellar eutectic spacings (lambda(E)) were measured from transverse sections of the samples. The functional dependencies of lamellar spacings lambda(E) ( lambda(Al2CuMg) and lambda(Al2Cu), in mu m), microhardness H-V (in kg/mm(2)), tensile strength sigma(T) (in MPa), and electrical resistivity rho (in Omega m) on the growth rate V (in mu m/s) were obtained as lambda(Al2CuMg)=3.05V(-0.31), lambda(Al2Cu)=6.35(-0.35),H-v = 308.3(V)(0.03) sigma(T)= 408.6(V)(0.14), and rho = 28.82 x 10(-8)(V)(0.11), respectively for the Al-Cu-Mg eutectic alloy. The bulk growth rates were determined as lambda(2)(Al2CuMg) V= 93.2 and lambda(2)(Al2Cu) V=195.76 mu m(3)/s by using the measured values of lambda(Al2CuMg), lambda(Al2Cu) and V. A comparison of present results was also made with the previous similar experimental results.