Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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Department: search.filters.department.Izmir Institute of TechnologySubject: search.filters.subject.Sintering

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  • Article
    Citation - WoS: 5
    Citation - Scopus: 5
    Ultrafast High-Temperature Sintering of Yttria-Stabilized Zirconia in Reactive N<sub>2</Sub> Atmosphere
    (Elsevier Sci Ltd, 2025) Karacasulu, Levent; de Beauvoir, Thomas Herisson; De Bona, Emanuele; Cassetta, Michele; Vakifahmetoglu, Cekdar; Sglavo, Vincenzo M.; Biesuz, Mattia
    So far, ultrafast high-temperature sintering (UHS) has always been carried out in an inert environment. In the present work, we investigated UHS of 3YSZ in nitrogen and argon atmosphere showing that "the atmosphere matters". Highly densified samples can be obtained in both environments but densification and grain growth are significantly retarded in N-2. Moreover, the phase evolution is strongly atmosphere-dependent with the samples treated in Ar remaining tetragonal and those treated under N-2 progressively reducing their tetragonality, eventually converting into cubic zirconia and rock salt oxynitride. The results can be explained by the incorporation of nitrogen within the ZrO2 lattice. Electrochemical impedance spectroscopy demonstrates that while the ionic bulk conductivity are marginally influenced by the sintering atmosphere, the grain boundaries' capacitive behavior strongly changes. After UHS under 30 A, excellent ionic conductors were obtained without substantial grain boundary-blocking effects.
  • Article
    Citation - WoS: 5
    Citation - Scopus: 8
    High Entropy (hftizrvnb)b2 Ceramic Particulate Reinforced Al Matrix Composites: Synthesis, Mechanical, Microstructural and Thermal Characterization
    (Elsevier Ltd, 2024) Süzer,İ.; Özçakıcı,Y.E.; Tekinşen,A.S.; Bayrak,K.G.; Mertdinç-Ülküseven,S.; Balcı-Çağıran,Ö.; Ağaoğulları,D.
    This study aims to introduce a novel type of particulate reinforced Al matrix composite. High entropy (HfTiZrVNb)B2 ceramic particulate reinforced Al matrix composites were produced via a combined process of different powder metallurgy methods. Firstly, boride compounds (HfB2, TiB2, ZrB2, VB2, NbB2) were synthesized in the laboratory scale using the related metal oxide, boron oxide, and magnesium by mechanochemical synthesis (MCS) and leaching processes under optimum conditions. Secondly, the synthesized and purified boride powders were mixed in equimolar ratios using a planetary ball mill for 72 h, and they were sintered at 2000 °C under 30 MPa via spark plasma sintering (SPS). Thirdly, equimolar high entropy (HfTiZrVNb)B2 bulks were crushed, converted into powder forms, and added into Al powders at different amounts as 1, 2, 5, 10, and 15 wt %. Lastly, these powder blends were mechanically alloyed in a vibratory ball mill for 6 h, cold pressed and pressureless sintered at 630 °C for 2 h. For characterization techniques, X-ray diffractometry (XRD), thermal analysis, scanning electron microscopy/energy dispersive spectrometry (SEM/EDS), density measurements using pycnometer and Archimedes' methods, microhardness and dry sliding wear tests were conducted on the sintered composites. The highest hardness (∼1.5 GPa) and the lowest wear rate (∼0.0012 mm3/Nm) were obtained in the Al-15 wt % (HfTiZrVNb)B2 sample. © 2024 Elsevier Ltd and Techna Group S.r.l.
  • Article
    Citation - WoS: 13
    Citation - Scopus: 13
    On the Temperature Measurement During Ultrafast High-Temperature Sintering (uhs): Shall We Trust Metal-Shielded Thermocouples?
    (Elsevier Sci Ltd, 2024) Biesuz, Mattia; Karacasulu, Levent; Vakifahmetoglu, Cekdar; Sglavo, Vincenzo M.
    Temperature measurement upon ultrafast high-temperature sintering (UHS) is a crucial task. Herein, we provide some arguments posing concerns about the use of metal-shielded thermocouples as temperature probes in UHS. The discussion is based on literature data and on some ad hoc experiments. In detail, we show at least two cases in the literature where the use of a shielded thermocouple causes a substantial underestimation of the UHS temperature. The argumentation is based on comparing the thermocouples read and the observed phase and microstructural evolution. Moreover, by means of a simple experimental design, we show that a metal shield on the thermocouple tip can substantially reduce the measured temperature. Since the metal shield is orders of magnitude more thermally conductive than the graphite felt used as heating element in UHS, it efficiently removes heat from the thermocouple tip region. As such, data acquired from shielded thermocouples must be treated with care.