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Conference Object Citation - WoS: 3Citation - Scopus: 4Production of Ultra-High Molecular Weight Polyethylene-Granite Composite Films by Gelation/Crystallization(Springer, 2016) Efe, Gozde Celebi; Ozaydin, Fevzi; Ucisik, Hikmet; Bindal, Cuma; Liang, HongThe present study reports on film of ultra-high molecular weight polyethylene (UHMWPE) containing 1 mass% granite composite produced by gelation/crystallization technique at 150 A degrees C from decalin solution. The morphology of UHMWPE-granite composite film was determined by using optical and scanning electron microscope, differential scanning calorimetry and Raman. Uniform dispersion of granite particles within ultra-high molecular weight polyethylene solution was the first step to achieve ultra-high molecular weight polyethylene-granite sheet samples with excellent properties. In differential scanning calorimetry analysis 50.1 % crystallinity of ultra-high molecular weight polyethylene-1 mass% granite composite was calculated from the endothermic peak area occurred around 142 A degrees C which correspond to melting point of composite. Mechanical property of ultra-high molecular weight polyethylene-1 mass% granite composite was tested with tensile test and shown to possess unique properties, in particular an increase of over 2.5 times in Young's modulus in comparison with pure ultra-high molecular weight polyethylene.Article Citation - WoS: 13Citation - Scopus: 17Effect of hydrogen on fracture locus of Fe-16Mn-0.6C-2.15Al TWIP steel(Pergamon-elsevier Science Ltd, 2020) Bal, Burak; Cetin, Baris; Bayram, Ferdi Caner; Billur, ErenEffect of hydrogen on the mechanical response and fracture locus of commercial TWIP steel was investigated comprehensively by tensile testing TWIP steel samples at room temperature and quasi-static regime. 5 different sample geometries were utilized to ensure different specific stress states and a digital image correlation (DIC) system was used during tensile tests. Electrochemical charging method was utilized for hydrogen charging and microstructural characterizations were carried out by scanning electron microscope. Stress triaxiality factors were calculated throughout the plastic deformation via finite element analysis (FEA) based simulations and average values were calculated at the most critical node. A specific Python script was developed to determine the equivalent fracture strain. Based on the experimental and numerical results, the relation between the equivalent fracture strain and stress triaxiality was determined and the effect of hydrogen on the corresponding fracture locus was quantified. The deterioration in the mechanical response due to hydrogen was observed regardless of the sample geometry and hydrogen changed the fracture mode from ductile to brittle. Moreover, hydrogen affected the fracture locus of TWIP steel by lowering the equivalent failure strains at given stress triaxiality levels. In this study, a modified Johnson-Cook failure mode was proposed and effect of hydrogen on damage constants were quantified. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.Conference Object Citation - Scopus: 2Static and Fatigue Behaviour of Recycled Thinsheet "ti-Al Based Composites Produced by Hot Forging Diffusion Process(Springer international Publishing Ag, 2024) Zambelis, Georges; Gatamorta, Fabio; Aslan, Ozgur; Miskioglu, Ibrahim; Bayraktar, EminWithin the framework of the common research project, the mechanical properties and fatigue behaviour of recycled thin sheet Ti-Al-based composites reinforced with atomized scrap aluminium (AA7075) and Nb elements have been evaluated. All the thin sheet sandwich structures were produced by the hot forging process, which is a semi-solid-forming process similar to partial melting hot forging. The effect of the chemical bonds during the production of these multifunctional sandwich composite structures was analysed using 3-point bending tests under static and dynamic (fatigue) loading conditions. Additional tensile tests have been carried out to evaluate the mating effect. Interface and microstructure of these composites have also been evaluated using scanning electron microscopy.Conference Object Citation - Scopus: 3Flow Curve Evaluation by Optic Strain Measurements and Force Balance at the Most Critical Section in the Neck Region of a Tensile Specimen(2011) Coruk,E.; Karadoǧan,C.Although higher strains can be reached during a tensile test of a ductile metal, only a small portion of this Information could be extracted from this ordinary tension test: Instability In the form of necking which prevents the mathematical evaluation of stresses and strains based on the elementary measurements, Is the basic obstacle. In this study, optic strain measurements around the most strained cross section of a tensile specimen, together with the force measurements, Is used to obtain the flow curve of the material up to strains of tensile rupture. GOM-Aramis System Is utilized as the optic strain measurement system. The measured strains are assumed to be totally plastic, making It possible to compute directly the yield stresses corresponding to the strains attained at the most strained point. Obtained flow curves are compared with the flow curves from the classical tension tests done by the help of precise tangible extensometers. Further comparisons with the result of hydraulic bulge tests and simulation of the tension test shows the applicability and reliability of the approach. © 2011 Wiley-VCH Verlag GmbH & Co. KGaA. Weinheim.
