Browsing by Publisher "International Institute for the Science of Sintering (IISS)"

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    Mechanical properties and hardness results of the medium frequency induction sintered iron based powder metal bushings
    (International Institute for the Science of Sintering (IISS), 2014) Çavdar U.; Atik E.; Ataç A.
    In this study; iron based powder metal (PM) bushing compacts were sintered via medium frequency induction heating system. Iron based powders were mixed with 2 wt.% copper (Cu), 0.3 wt.% carbon (C) and 1 wt.% zinc stearat (Zn-st) via V-Type mixer. PM compacts were sintered by 2 different sintering processes. One of them was conventional sintering method other was medium frequency induction sintering method. In conventional sintering process, PM bushing compacts were sintered under inert environmental at 11200C for 30 minutes. In medium frequency induction sintering process, PM bushing compacts were sintered between 30-50 kHz frequency (Medium frequency) at 2 kW, 11200C for 1 or 3 minutes under atmospheric environmental. Mechanical properties, densities and micro hardness’ were investigated for all sintered processes. SEM and micro structural images were taken from polished broken surface of the sintered PM bushing compacts. 3 minutes induction sintered compacts were reached the compressive strength, microhardness and density values of the conventional sintered PM bushing compact. © 2014,International Institute for the Science of Sintering (IISS). All rights reserved.
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    From metal chips to composite: Effect of age-hardening on mechanical and wear properties of al2 o3 reinforced aa7075 composites
    (International Institute for the Science of Sintering (IISS), 2020) Durmuş H.; Gül C.; Çömez N.; Uzun R.
    Aluminum metal matrix composites were used in various fields such as aircraft, underwater, automobile, aerospace. Several fabrication techniques were used for the production of these composites. Among the various methods, the powder metallurgy route provides dimensional accuracy and high production rates. In this paper, metal matrix composites that include 7075 aluminum alloy chips and Al2O3 particles were produced by using a hot pressing. The effect of reinforcement amount and T6 heat treatment on the mechanical and wear properties of the composites were investigated. Al2O3 particles were added by weight of 5, 10 and 15 % and the composites were produced by hot pressing. T6 heat treatment consisted of a solution treatment at 480 °C for 2 h and artificially aging process at 120 °C for 24 h. Wear resistance of the composites was determined by a ball-on-disc dry sliding wear test. Brinell Hardness of the composites tended to increase with the increasing Al2O3 reinforcement up to 10 wt.% and with T6 treating. Particle reinforcement improved the wear resistance up to 10 wt.% Al2O3. In addition, volumetric material loss tended to decrease after the aging process. © 2020 Authors.
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    Cost analysis of T6 induction heat treatment for the aluminum-copper powder metal compacts
    (International Institute for the Science of Sintering (IISS), 2020) Taştan M.; Gökozan H.; Çavdar P.S.; Soy G.; Çavdar U.
    This work compares an energy cost and an energy consumption results of the 4 wt.% cupper mixed aluminum based powder metal (PM) compacts processing under induction or furnace heating. Total power and energy consumptions and total energy costs per kilogram and compact have been analyzed. T6 precipitation heat treatment applications have been applied with two different methods, one with 2.8 kW, 900 kHz ultra-high frequency induction heating system (UHFIHS), other with 2 kW chamber furnace. In the first method, Al-Cu PM compacts have been heated by induction at 580 °C in one minute and then cooled down by water. Afterwards, the samples have been heated 170, 180, 190 and 200 °C respectively for artificial ageing and cooled naturally. In the second treatment, unlike the first study, Al-Cu PM compacts are heated by chamber furnace at 540 °C in 5 hours and cooled by water. Then PM compacts are artificially aged at 190 °C in 10 hours with same furnace. During both processes, energy and power consumptions for each defined process have been measured. Optimum heat treatment of the induction is determined. The cheaper energy cost is obtained by the induction heat treatment. © 2020 Authors. Published by association for ETRAN Society.
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    Microstructure and Mechanical Properties of Ni Matrix B4C Reinforced Functionally Graded Composites
    (International Institute for the Science of Sintering (IISS), 2021) Caligulu U.; Durmus H.; Akkas M.; Sahin B.
    In this study, microstructure and mechanical properties of nickel matrix B4C reinforced functionally graded composites produced by powder metallurgy method were investigated. Samples with Ni+5% B4C, Ni +10% B4C, Ni+ 15% B4C and Ni+ 20% B4C compositions were sintered at 900 and 1050oC for 60 minutes. Microhardness and wear tests along with optical microscopy, scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) and X-ray diffraction (XRD) analyses were carried out to determine the mechanical properties, microstructure and phase composition of the samples. The results indicated that hardness and wear resistance increased with increases of B4C amount in nickel matrix. © 2021 Authors. Published by association for ETRAN Society.
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    Characterization of SiO2 Sol-Gel Coated Ti6Al4V Alloy Obtained by using TEOS and GPTMS
    (International Institute for the Science of Sintering (IISS), 2021) Gül C.; Albayrak S.; Durmuş H.; Çömez N.
    Synthesis of silicon oxide (SiO2) via the sol-gel method and SiO2 coating ability on to Ti6Al4V alloy were investigated, in the novel study. Ti6Al4V alloy is the most used alloy in biomedical applications due to its many advantages. However, it has a minor disadvantage like releasing ions into the human body. In this study, the substrate material Ti6Al4V alloy samples were coated using the sol-gel method with alkoxysilane solutions (tetraethyl orthosilicate, TEOS; Si(OC2H5)4 and glycidoxypropyltrimethoxysilane, GPTMS; C9H20O5Si) containing the unit of prepared Si(OR)n after the surface preparations were made. The prepared solutions were examined using thermal analysis methods and the process temperatures to be applied to the coatings were determined according to the results of the analysis. Coated samples were subjected to aging, drying, and sintering processes at specified temperatures. The morphologies and structures of the samples were investigated by using a scanning electron microscope with energy-dispersive spectroscopy (SEM-EDS) and X-ray diffraction (XRD). The sol-gel coating ability of the silicon oxide on the surface of the Ti6Al4V alloys has been discussed. The results demonstrate that cracks were observed in coating produced by TEOS precursor whereas the coatings used GPTMS precursor exhibited crack-free surface independently of dipping number. The crack formation tended to reduce with increasing dipping number of coatings produced by TEOS precursor. Distances between coating islets gradually became smaller as the number of dippings increased, and the continuity of the coatings increased. It has been observed that SiO2 coating layers produced with GPTMS are obtained in a more continuous and crack-free form than the layers produced with TEOS. © 2021 Authors. Published by association for ETRAN Society.