Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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Access type: Open accessSubject: search.filters.subject.Alloys

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  • Master Thesis
    Effect of Arc Deposition and High Power Impulse Magnetron Sputter Coatings on the Performance of Tools for Machining Various Ferrous Materials and Ti6al4v Alloys
    (Izmir Institute of Technology, 2023) Nohuz, Mine; Davut, Kemal; Davut, Kemal; 03.09. Department of Materials Science and Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    In this thesis, the performance of different coating techniques in machining various steels and Ti6Al4V is investigated. Currently, most of the carbide tools with the coating because of the tool life. In order to increase the productivity of the manufacturing processes and to use new materials, the research on the coating of cutting tools has been increased. Recently, the interest in physical vapor deposition has increased because the tool life is increased for many difficult-to-machine materials and difficult machining conditions. Two types of PVD coating were used in this work. The surfaces of the coated tools were examined under scanning electron microscope. The effects of cathodic arc deposition and high pulse magnetron sputtering on tool performance were investigated on various workpieces such as 4140 and CK45 steels, D2 tool steel (60HRC), GG25 cast iron and also on Ti6Al4V alloy. In the performance tests, the cutting forces were measured over a period of time and the wear patterns were recorded. The results indicate that HIPIMS coated tools perform better in operations where normal load is low and torsion forces are high. Those tools also work better in materials harder than 250 BHN. The better performance of HIPIMS coated tools were attributed to their less smooth and droplet free surfaces.
  • Master Thesis
    Processing and Characterization of Scandium Added A356 Cast Alloy
    (Izmir Institute of Technology, 2021) Öner, Cezmi; Kandemir, Sinan; Öner, Cezmi; Kandemir, Sinan; 01. Izmir Institute of Technology; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering
    As a result of today's rapid technological developments and the rapid consumption of reserves in the world, the search for alternative materials has started. One of the biggest examples of this is wheel alloy. Ti5B1, one of the additives of the A356 Al alloy that is generally used in automobile wheels, allows to reduce the grain size in the alloy. In the event of depletion of possible Ti5B1 resources, there will be a need to use alternative materials instead. Based on this purpose, materials that can be used instead of Ti5B1 were examined. Scandium (Sc) as a rare earth element was found to be the least studied element with A356. A number of Sc-based studies with other aluminum alloys were reported and it was decided to work with this element for A356 alloy. In the thesis, the effect of Sc adjunction on the mechanical properties of A356 aluminum alloy after the permanent die casting process was investigated. Sc added to the A356 alloy at a ratio of 0.2, 0.4 and 0.6 weight percent, respectively. Optical microscopy (OM), Scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) were used for the microstructural analyses in this study. According to the experiments and results obtained in this study, it was observed that Sc can significantly increase the mechanical properties of the A356 alloy in terms of tensile strength and hardness values. Overall, it was found that the addition of 0.2 wt.% Sc to the A356 alloy could achieve a maximum tensile strength of 258.31 MPa compared to 242.54 MPa for the reference sample without Sc. No significant improvement in tensile strength results was observed when more than 0.2 wt.% Sc was added to the alloy. As for the hardness, the sample containing 0.2 wt.% Sc reached a maximum Brinell hardness of 75.01 HB compared to 77.58 HB for the unmodified sample. As a result, the amount of porosity increased with Sc added to the alloy, and an increase in dendrite arm lengths occurred. Due to this length in the arms, a decrease in fracture toughness occurred. In addition, there was no significant improvement in hardness.