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    Design of hybrid composites from scrap aluminum reinforced with (SiC+TiO2+Gr+Ti+B)
    (Springer New York LLC, 2017) Kurşun, Ali; Ferreira, Lygia Maria Policarpio; Bayraktar, Emin; Miskio?lu, İbrahim
    Hybrid Metal Matrix Composites (HMMCs) have very light weight, high strength, and show better resistance to corrosion, oxidation, and wear. Impact resistance is an especially important property of these HMMCs which is essential for automotive applications. In this study, hybrid aluminum matrix composites were designed through the powder metallurgy route. As matrix, fresh scrap aluminium chips (AA2014), byproduct of machining, were used. Silicon carbide (SiC), boron, titanium, titanium oxide (TiO2) and graphite (Gr) particles were used as reinforcement elements for the present work. The hybrid MMCs were prepared with SiC (5, 10 and 15 % by weight) as a main reinforcement and also certain amounts of Ti, B, TiO2 and graphite powders were added in the matrix. Within the framework of the present study, an original idea of producing a hybrid composite has been developed by using scrap aluminum (AA2014) chips. This consist of the mixing, blending and compacting of aluminum chips through press moulding and sintering. The influence of the reinforcement particles on the mechanical behavior of these composites was evaluated. Microstructure of each composite was analyzed by Scanning Electron Microscope (SEM). © The Society for Experimental Mechanics, Inc. 2017.
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    Effect of impactor shapes on the low velocity impact damage of sandwich composite plate: Experimental study and modelling
    (Elsevier Ltd, 2016) Kurşun, Ali; Şenel, Mehmet; Enginsoy, Halil Murat; Bayraktar, Emin
    An experimental and numerical analysis of the influence of impactor shapes on the low velocity impact performance of aluminium sandwich composite plates has been carried out. The aluminium composite panels were manufactured by using two aluminium sheets and a low density polyethylene core under heat and pressure, which shows the outstanding properties of low weight, good rigidity and impact resistance. Experimental tests were performed using drop weight test machine, samples were impacted using steel conical, ogival, hemispherical and flat impactors, all 12 mm in diameter, for different initial impact energies of 29.43 J and 44.15 J and specimen thickness of 4 mm containing three different parts (0.5 + 3.0 + 0.5). A three dimensional non-linear finite element model is developed for simulating the impact behaviour of sandwich composite plate and the ABAQUS/Explicit commercial program was used. The face sheet material aluminium alloy 3003-O of the plate was modelled as isotropic with elastic-plastic characteristics. The description of the material characteristic of the attenuator was made by means of the Johnson-Cook elastic-plastic law. The material constitutive law of the Al 3003 plates has been implemented in a user-defined subroutine UMAT. The foam core was modelled as a crushable foam material. The finite element results showed a good correlation to the experimental data in terms of contact-force histories, energy histories, absorbed energy, and failure of the sandwich composite was observed between the experimental data. © 2015 Elsevier Ltd.
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    Experimental and numerical study of alumina reinforced aluminum matrix composites: Processing, microstructural aspects and properties
    (Elsevier Ltd, 2016) Kurşun, Ali; Bayraktar, Emin; Enginsoy, Halil Murat
    Co-continuous alumina-aluminum composite materials with excellent physical and mechanical properties offer great potentials for lightweight, wear resistant, and high-temperature applications. They combine metallic properties of matrix alloys (ductility and toughness) with ceramic properties of reinforcements (high strength and high modulus), leading to greater strength in shear and compression and higher service-temperature capabilities. Composite materials prepared from a liquid-phase displacement reaction present a unique microstructure in which each phase is a continuous network penetrated by the network of the other constituent. In this study, aluminum-alumina matrix composites reinforced with glass bubbles with low thermal and electrical conductivities are presented. Different characterization techniques were used to determine physical-mechanical properties. Porosity and density measurements were carried out by means of helium gas pycnometer and basic materials parameters were compared such as effect of the sintering process, thermal conductivity, and percentage of the wax. Drop weigh tests, semi static compression tests and also scratch tests were applied to measure the general mechanical and damage behavior of these composites. Microstructural and fracture behavior were evaluated by Scanning Electron Microscopy (SEM). A three dimensional non-linear finite element model was developed for modeling the impact and compression behavior of alumina reinforced aluminum matrix composite materials. For this stage, ABAQUS/Explicit commercial program was used. The finite element results have shown a good correlation with the experimental data in terms of contact-force and energy histories and also deflection phenomena of the alumina reinforced aluminum matrix composites during the impact was observed between the experimental data. © 2016 Elsevier Ltd. All rights reserved.
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    Low cost manufacturing of aluminium-alumina composites
    (Taylor and Francis Ltd., 2015) Kurşun, Ali; Bayraktar, Emin; Robert, Maria Helena
    Co-continuous alumina–aluminium composite materials with excellent physical and mechanical properties offer great potentials for lightweight, wear-resistant and high-temperature applications. They combine metallic properties of matrix alloys (ductility and toughness) with ceramic properties of reinforcements (high strength and high modulus), leading to greater strength in shear and compression and higher service temperature capabilities. Composite materials prepared from a liquid-phase displacement reaction present a unique microstructure in which each phase is a continuous network penetrated by the network of the other constituent. In this study, aluminium–alumina matrix composites reinforced with glass bubbles with low thermal and electrical conductivities are presented. Different characterisation techniques were used to determine physical–mechanical properties. Porosity and density measurements were carried out by means of helium gas pycnometer and basic materials parameters were compared such as effect of the sintering process, thermal conductivity and percentage of the wax. Drop weigh tests, semi-static compression tests and also scratch tests were applied to measure the general mechanical and damage behaviour of these composites. Microstructural and fracture behaviour were evaluated by scanning electron microscopy. © 2016, © 2016 Taylor & Francis.