Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 2Citation - Scopus: 2Sintering Under High Heating Rates(Annual Reviews, 2025) Karacasulu, Levent; Karacasulu, Levent; Maniere, Charles; Ahmetoğlu, Çekdar Vakıf; Vakifahmetoglu, Cekdar; Marinel, Sylvain; Biesuz, Mattia; 03.09. Department of Materials Science and Engineering; 01.01. Units Affiliated to the Rectorate; 01. Izmir Institute of Technology; 03. Faculty of EngineeringRapid sintering using a high heating rate is growing in technological and scientific interest. This is motivated by the promise of reducing the carbon footprint of sintering and developing materials with properties and microstructures different from those achievable by conventional heating. For instance, rapid heating can induce suppression of grain growth, the possibility of obtaining modified space charges and elemental segregations, and the development of out-of-equilibrium materials. Severe challenges still exist for the industrial exploitation of rapid sintering technologies, and, nowadays, only fast firing can be considered mature. Most of these limitations are related to the homogeneity of the sample and the possibility of obtaining complex shapes. This review investigates developments in rapid sintering by comparing different processes, suggested mechanisms, and future challenges.Article Citation - WoS: 1Citation - Scopus: 1Fast Firing Technique for Martian Regolith Simulant: Advancing Isru Capabilities(Academic Press inc Elsevier Science, 2025) Ahmetoğlu, Çekdar Vakıf; Karacasulu, Levent; Vakifahmetoglu, Cekdar; Biesuz, Mattia; 03.09. Department of Materials Science and Engineering; 01.01. Units Affiliated to the Rectorate; 01. Izmir Institute of Technology; 03. Faculty of EngineeringIn-Situ Resource Utilization (ISRU) approaches hold significant importance in plans for space colonization. This work explores a different ISRU concept applying fast-firing, a robust and well-known industrial process, to Mars regolith simulant (MGS-1). The fast-fired specimens were compared to the ones obtained by conventional sintered under low heating rates. When the holding time at the firing temperature is longer than 15 min, fast-fired specimens exhibited higher density and flexural strength (> 35 MPa) than conventional sintering. For both processes, the bulk density values and the mechanical properties of the regolith compacts were enhanced with increasing dwell time. This was attributed to higher heating rates changing the densification/crystallization kinetics involving the basalt glass in the regolith composition. Specifically, high heating rate promotes sintering over crystallization. On these bases, fast firing can be considered a potential candidate for ISRU on Mars.Article Citation - WoS: 2Citation - Scopus: 1Pressureless Synthesis and Consolidation of the Entropy-Stabilized (hf<sub>0.25</Sub>zr<sub>0.25< Composite by Ultra-Fast High-Temperature Sintering (uhs)(Elsevier Sci Ltd, 2025) Karacasulu, Levent; De Bona, Emanuele; Karacasulu, Levent; Biesuz, Mattia; Sglavo, Vincenzo M.; Akhtar, Farid; 01.01. Units Affiliated to the Rectorate; 01. Izmir Institute of TechnologyEntropy-stabilized Ultra High-Temperature Ceramics (UHTC) offer a groundbreaking solution to the challenges of extreme environments, showcasing enhanced mechanical properties, thermal stability, and resistance to oxidation at high temperatures. The consolidation of UHTC by ultra-fast high-temperature sintering (UHS) significantly reduces processing times and temperature and can produce dense high-performance ceramics with superior mechanical properties. This study reports the pressureless synthesis and consolidation of the entropy-stabilized (Hf0.25Zr0.25Ti0.25V0.25)B-2-B4C composite through UHS within 1 minute, starting from transition metal diboride powders. B4C acts as an effective sintering aid, promoting the densification of the system and the formation of a nearly single-phase hexagonal diboride with a diboride-eutectic phase. Furthermore, a secondary minor hexagonal phase rich in V and Zr is formed close to the eutectic regions. Sintering currents of 40 A were necessary to reach densities higher than 90 % under pressureless conditions, achieving nano hardness higher than 27.3 GPa, comparable with high-entropy diborides produced by Spark Plasma Sintering. The study highlights the entropy-stabilized phase formation, diffusion, densification, and grain growth mechanisms involved during UHS. The work contributes to the understanding of entropy-stabilized ceramics produced by UHS as a faster and less energy-consuming process than conventional sintering methods.Article Citation - WoS: 1Citation - Scopus: 1Pressureless Joining of Soda Lime Silicate Glass Using Polysilazane-Derived Silica at Near-Room Temperature(Elsevier Sci Ltd, 2025) Ahmetoğlu, Çekdar Vakıf; Karacasulu, Levent; Pastorelli, Virginia; Vakifahmetoglu, Cekdar; Sglavo, Vincenzo M.; Ferraris, Monica; Soraru, Gian D.; 03.09. Department of Materials Science and Engineering; 01.01. Units Affiliated to the Rectorate; 01. Izmir Institute of Technology; 03. Faculty of EngineeringPerhydropolysilazane (PHPS) pre-ceramic polymer was used to join soda lime silicate glass at temperatures below 200 degrees C under pressureless conditions. The results show that: (i) the junction material is largely converted to silica at 100 degrees C and fully converted to glass at 150 degrees C; (ii) the samples treated at room temperature and 100 degrees C show a perfectly dense and clean bond, whereas porosity develops starting from 150 degrees C as a result of the hydrolysis reactions and solvent evaporation; (iii) a maximum tensile bond strength of about 5-6 MPa is obtained after treatments at 100 degrees C. Remarkably, after treatment at 500 degrees C, the junction remains intact. These preliminary findings provide the first successful attempt regarding the use of PHPS as a joining material to produce inorganic and transparent bonds for glass at relatively low temperatures.Article Citation - WoS: 8Citation - Scopus: 12Synthesis of Potassium-Sodium Niobate (Knn) From Nbo2(Elsevier, 2021) Karacasulu, Levent; Ahmetoğlu, Çekdar Vakıf; Bortolotti, Mauro; Vakifahmetoglu, Cekdar; 03.09. Department of Materials Science and Engineering; 01.01. Units Affiliated to the Rectorate; 01. Izmir Institute of Technology; 03. Faculty of EngineeringKxNa1-xNbO3 (0 < x < 1) were synthesized via hydrothermal method using niobium dioxide (NbO2) as the niobium source instead of the most common one, Nb2O5. Potassium-rich KxNa1-xNbO3 (x > 0.5) was obtained from 8 M total hydroxide concentration after 6 h of reaction at 200 degrees C. Rietveld refinement of the XRD data revealed that all samples exhibited the secondary NaNbO3 phase. However, the lowest amount (3.74 vol%) was obtained for 24 h of reaction under 10 M alkaline solution. After 3 h of reaction, dodecahedra shaped hexaniobate phase (KxNa8-xNb6O19.nH(2)O) was observed. Those structures were, subsequently, replaced by similar to 3 mu m cube shaped KNN crystals, obtained under 10 M reaction in 24 h time period.