Mechanical Engineering / Makina Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/4129
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Article Citation - WoS: 3Citation - Scopus: 5Electrical and Thermal Properties of the Gasb-Fega1.3 Eutectic(MAIK “Nauka/Interperiodica”, 2004) Aliev, M. I.; Khalilova, A. A.; Arsaly, D. G.; Ragimov, R. N.; Tanoğlu, MetinThe electrical conductivity, thermoelectric power, Hall coefficient, and thermal conductivity of the GaSb-FeGa1.3 eutectic were measured in a wide temperature range at different relationships between the directions of the electric current, heat flux, magnetic field, and needlelike metallic inclusions. The results are interpreted in terms of electronic and phonon processes. The metallic inclusions are shown to have a significant effect on the transport properties of the eutectic.Conference Object Microstructure-Performance Relation in Pmma-Based Open-Cell Porous Materials for High Pressure Ceramic Sanitaryware Casting(Trans Tech Publications, 2004) Ergün, Yelda; Dirier, C.; Yılmaz, M.; Tokman, C.; Tanoğlu, MetinThe ceramic whiteware/sanitaryware industry is rapidly undergoing to implement high-pressure casting techniques for ceramic article production. In these techniques, materials with open pore microstructure that allows drainage of water under applied pressure are needed. The polymethyl methacrylate (PMMA) based polymeric porous materials have become the most suitable type of materials for this purpose because of their short casting periods and high service lives. However, the superior service life and performance of these materials are closely related to the microstructure. In the present study, the porous materials with various compositions of the constituents in the emulsion were produced to effect the microstructure of PMMA-based materials. The variations on the pore microstructure were interrelated to the performance of the material for high-pressure sanitaryware casting. The pore morphology and water permeability of the samples was measured using optical and SEM microscopy and permeability measurement techniques, respectively. The compressive collapse stress and modulus values were determined by performing compression testing. The results showed a significant interrelation between microstructure and the performance of the PMMA-based ceramic mould materials.Conference Object Citation - WoS: 5Citation - Scopus: 6Development of Si-O Based Ceramic Matrix Composites Produced Via Pyrolysis of a Polysiloxane(Trans Tech Publications, 2004) Akkaş, Hatice Deniz; Öveçoğlu, M. L.; Tanoğlu, MetinPyrolytic conversion of a preceramic polymer, poly(phenyl)siloxane has been investigated to develop ceramic matrix composites (CMCs) at low temperatures with high dimensional stability. Furthermore, the thermal transformation of the polymer precursor under inert atmosphere was monitored. For this purpose, poly(phenyl)siloxanes were cured at about 200°C for 2 hours under air and pyrolysed at various temperatures in the range of 900 - 1500°C for 1 hour under inert argon atmosphere. The products of the pyrolytic conversion were analyzed using X-ray diffraction (XRD), thermal analysis (TG and DTA) and scanning electron microscopy (SEM) coupled with EDX analyzer. It was found that pyrolysis under inert atmosphere up to 1300°C led to amorphous silicon oxycarbide (SiOxCy) ceramics. Conversions at higher temperatures caused the transformation into the crystalline β-SiC phases. Moreover, to obtain composite monoliths inert Al2O3 and active Ti and Si particulates were incorporated into the polymer as fillers employing compressive moulding at moderate temperatures. During pyrolysis, cross-linked green compacts of the particulate/polymer system were converted into ceramic body and the microstructural parameters and the effects of the filler type on the microstructure were investigated.Conference Object Citation - WoS: 6Citation - Scopus: 5Electrical and Microstructural Properties of Superconducting Mgb 2/Mg Composites(Trans Tech Publications, 2004) Eğilmez, Mehmet; Günel, Aylin; Okur, Salih; Tanoğlu, Metin; Özyüzer, LütfiMgB2/Mg composites were prepared to improve mechanical properties of brittle superconducting MgB2. MgB2 and Mg powders were mixed at different weight ratios and uniaxially pressed in a cylindrical dye at 0.5 GPa and at various temperatures for two hours to prepare MgB2/Mg composites. X-ray diffraction, SEM and EDX were used for phase identification and microstructural characterization. In addition to the main MgB2 and Mg phases, the microstructural studies have indicated the presence of a minor amounts of second phases, namely MgO and B-rich compounds. The surface morphology, grain size and porosity ratio of the samples prepared under various temperatures were also investigated. The resistivity measurements were performed in the range of room temperature to 15 K. The effect of excess Mg and secondary phases on critical temperature of MgB2/Mg composites were studied.