Thermal analysis of eutectic modified and grain refined aluminum-silicon alloys

İslamoğlu, H. Erol
A series of AlSi9Mg alloys were prepared and tested to reveal the effect of addition sequence and timing of grain refiner and eutectic modifier. AlSr10 master alloy was used as an modification reagent, and also for grain refiner AlTi5B master alloy was used. The depression at the eutectic temperature due to the addition of modifier and decrease in the amount of undercooling at the liquidus due to the presence of grain refiner were examined by the cooling curves which were obtained by the Alu-Therm instrument, which is the aluminum thermal analyzer of the Heraeus Electro-Nite. The alloys that were both modified and grain refined were subsequently poured as tensile test specimen shapes in permanent die casting mould for four times at 60 minutes time intervals, meanwhile thermal analysis of the alloys were also made. In this work the effect of grain refinement and modification agent, also the determination of the optimum time to pour after adding these agents were studied by aluminum thermal analyzer. The parameters obtained from this analyzer are compared with the microstructures; to see the effect of these agents on mechanical properties, hardness, tensile strength and percent elongation values were investigated. In this study the possibility of predicting the mechanical properties prior to casting by thermal analysis method was examined by regression analysis method. By this method relationship between thermal analysis parameters and mechanical properties was established.


Texture softening and strain instability in F.C.C. metals: Plane-strain deformation
Öztürk, Tayfur; Davies, Gwilym J. G (Elsevier BV, 1987-9)
An analysis was carried out into texture induced softening and the resulting strain instability in plane-strain deformation. A macroscopic model was employed in the analysis which viewed the deformation as the juxtaposition of suitably disposed positive and negative simple shears. With this model, the textural contribution to the rate of deformation hardening was computed in terms of a texture softening factor, S, this in a form that could readily be incorporated into the relevant conditions for strain inst...
Microstructural and elecrochemical characterization of Ti-6A1-4V ELI alloy
Topçuoğlu, Melih; Aydınol, Mehmet Kadri; Department of Metallurgical and Materials Engineering (2006)
In this study, the evolution of structure and the relationship between microstructure and corrosion behavior of the Ti-6Al-4V ELI (Extra Low Interstitial) alloy was investigated in Ringer’s solution at 37 ± 0.1 oC. Initially, different heat treatments were performed in order to obtain several microstructures which were; Widmanstätten α for furnace cooling (FC), basket-weave α for air cooling (AC), martensite (α') for water quenching (WQ) from 1060 oC, and aged martensite for ten hours at 500, 600, 700, 800,...
Thickness effects in hydrogen sorption of magnesium/palladium thin films
Gharavi, Ayshe Gharemeshg; Öztürk, Tayfur; Department of Metallurgical and Materials Engineering (2012)
Magnesium (Mg) thin films with various thicknesses ranging from 50 to 1000 nm capped with nominally 20 nm Palladium (Pd) were prepared by a thermal evaporation unit. A total of 25 glass substrates were used in each experiment. The unit had a rotatable macro shutter, rectangular in shape, rotation axes opposite to the Mg source, which allowed controlled exposure of the substrates. Thin films of 50, 100, 150, 200, 300, 400, 500, 600, 800 nm and 1000 nm were produced in a single experiment. Hydrogenation and d...
Investigation of the effect of orientation and heat treatment on the stress corrosion cracking susceptibility of 7050 aluminium alloy
Çevik, Gül; Doruk, Mustafa; Department of Metallurgical and Materials Engineering (2004)
In the present work, the effect of variation in specimen orientation and heat treatment on the Stress Corrosion Cracking (SCC) susceptibility of 7050 aluminum alloy was investigated in 3,5% NaCl solution and under freely corroding conditions. For this purpose, Constant Extension Rate Tests (CERT) was performed on precracked Compact Tension (CT) specimens and the Direct Current Potential Drop technique was applied to measure the crack lengths. In addition to crack length versus time curves, the relationship ...
Investigation and development of possible leaching processes for recovery of zinc and lead from çinkur leach residues
Sunkar, Ahmet Semih; Topkaya, Yavuz Ali; Department of Metallurgical and Materials Engineering (2005)
The major aim of this study was to investigate various leaching methods for the recovery of zinc and lead from blended neutral leach residues of Çinkur having a composition of 12.59 % Zn, 15.21 % Pb, 6.45 % Fe, 0.054 % Cd. Initially water leaching tests were performed at various conditions of leaching temperature, reaction time and particle size. The optimized conditions for water leaching were found to be 2 h, 95?C and 250 g/l pulp density with a final pH of 5.9. However, the zinc recovery value of 10.26 %...
Citation Formats
H. E. İslamoğlu, “Thermal analysis of eutectic modified and grain refined aluminum-silicon alloys,” M.S. - Master of Science, Middle East Technical University, 2005.