Hot dynamic consolidation of aifevsi alloy powders

Kotan, Şevkiye Ezgi
The experimental alloy powders of 1% Mg treated Al-8Fe-1.8V-8Si were obtained by air atomization. The screen analysis of powders was made by sieves with meshes ranging from +90æm, +63æm, +53æm, +45æm, +38æm to -38æm. Unreinforced and TiC particulate reinforced specimens were produced by hot dynamic consolidation which is known as hot swaging. Powders were canned into pure aluminium tubes of about 10cm length and 2.2cm diameter. Single action and double action cold pressing were applied to some of the specimens before hot dynamic compaction and some specimens of canned loose powder were also processed. The diameters of the hot compacts were decreased in a two step process by swaging machine (rotary dynamic compaction). During the first step, after canning, compacts had been held at 480°C for 1 hour and swaged, thus the diameter decreased from 2.2 cm to 1.97cm. Secondly, the compacts were reheated to 480ðC and held for 1 hour and further swaged to obtain a diameter decrease from 1.97cm to 1.54cm. Generally, the microstructures of the hot dynamic compacted specimens were homogeneous except the specimens produced by using -63 æm +53 æm powder size fraction. By SEM study, a vanadium free cross like AlFeSi phase was observed near the outer regions of the specimen. No considerable coarsening of the dispersoids was observed after hot dynamic compaction of +63 æm size powder. For -90æm +63æm size powders, maximum flexural strength values obtained by three point bending test increased by addition of 10% TiC to from 152 MPa to 285 MPa at double pressed condition and from 76MPa to 190MPa at loose powder canning condition. By hardness tests, it was observed that hardness values were inversely proportional to powder size and increased from 107 BHN to 147 BHN for corresponding powder size range of +90æm to -38æm. Porosity values obtained by Archimedes principle for single pressing


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Tahmasebifar, Aydin; Evis, Zafer; Department of Engineering Sciences (2011)
The aim of this study was to investigate the microstructure and mechanical properties of pure tricalcium phosphate (TCP) and tricalcium phosphates doped with aluminum (Al3+) and fluoride (F-) ions at different compositions. TCP was synthesized via precipitation method and sintered at 1100C for 1 and 5 h. It was observed that density and relative density of the sintered materials were decreased by extending the sintering time. Increased densities were achieved upon Al3+ and/or F- doping. For structural anal...
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Sultan, Abdelrahman; Karakaya, İshak; Department of Metallurgical and Materials Engineering (2005)
The oxidation of three different steels used in the construction of petroleum refineryheaters was investigated by using thermogravimetric analysis technique (TGA). C-5,P-11, and P-22 steel samples were tested in two different oxidizing environments; air and CO2+N2+H2O (that simulates the combustion products of natural gas) at two different temperatures; 450oC and 500oC. In air oxidation P-22 had the best oxidation resistance among the three steels at two temperatures. In CO2+N2+H2O environment,C-5 possessed...
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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...
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Esen, Ziya; Bor, Şakir; Department of Metallurgical and Materials Engineering (2007)
In the present study, production of titanium and Ti6Al4V alloy foams has been investigated using powder metallurgical “space holder technique” in which magnesium powder were utilized to generate porosities in the range 30 to 90 vol. %. Also, sintering of titanium and Ti-6Al-4V alloy powders in loose and compacted condition at various temperatures (850-1250oC) and compaction pressures (120-1125 MPa), respectively, were investigated to elucidate the structure and mechanical properties of the porous cell walls...
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Eken, Ali Erdem; Özenbaş, Ahmet Macit; Department of Metallurgical and Materials Engineering (2008)
Magnetite (Fe3O4) thin films were prepared by a sol-gel process in which, a solution of iron (III) nitrate dissolved in ethylene glycol was applied on glass substrates by spin coating. Xerogel films were obtained by drying the coated films at 110 °C. The films were sintered between 300 °C and 450 °C in order to observe the phases existing in the films at different temperatures. Coating solution showed Newtonian behaviour and viscosity was found as 0.0215 Pa.s. DTA analysis showed that, sintering temperature...
Citation Formats
Ş. E. Kotan, “Hot dynamic consolidation of aifevsi alloy powders,” M.S. - Master of Science, Middle East Technical University, 2005.