Browsing by Author "Süzer, İlayda"

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Citation - WoS: 8
Citation - Scopus: 9
Graphene Nanoplatelet Reinforced Al-Based Composites Prepared From Recycled Powders Via Mechanical Alloying and Pressureless Sintering
(Elsevier Science Sa, 2024) Süzer, İlayda; Hayırcı, Sena Burcu; Boyacı, Ege; Deniz, Ayşe; Mertdinç Ülküseven, Sıddıka; Öveçoğlu, Mustafa Lutfi; Ağaoğulları, Duygu
This study reports on the powder metallurgy preparation and characterization of aluminum-graphene nanoplatelet (Al-GNP) composites synthesized using recycled Al powders. Recycled Al and GNP powders (0.1-1 wt%) were mechanically alloyed (MA'd) for 4 h, followed by cold pressing (at 450 MPa) and pressureless sintering at 590 degrees C for 2 h. Starting powders were analyzed using an optical emission spectrometer (OES) and a Raman spectrometer. Also, MA'd powders and sintered samples were characterized using an X-ray diffractometer (XRD), a scanning electron microscope/energy dispersive spectrometer (SEM/EDS), and a differential scanning calorimeter (DSC). Particle size analyses, pycnometer, and Archimedes' densities, Vickers microhardness, dry-sliding wear, and compression tests were also conducted. The Al4C3 formation was observed in the XRD patterns of sintered compositions. The highest and lowest relative densities were measured for the 1 wt% and 0.1 wt% GNP reinforced samples as 97 % and 92 %, respectively. The highest hardness value was obtained as approximately 1.31 GPa for 1 wt% GNP reinforced. With the addition of reinforcement GNP, the wear rate developed to approximately 0.00225 mm3/Nm. The compressive strength increased from nearly 70 MPa to 162 MPa.
Room-Temperature Synthesis of Refractory Borides: a Case Study on Mechanochemistry and Characterization of Mo-Borides and W-Borides
(Elsevier Sci Ltd, 2025) Süzer, İlayda; Akbari, Amir; Kaya, Faruk; Mertdinç Ülküseven, Sıddıka; Derin, Bora; Öveçoğlu, M. Lütfi; Ağaoğulları, Duygu
Mo-boride and W-boride powders were produced from native boron oxide, magnesium, and related metal oxide starting materials by mechanochemical synthesis (MCS) followed by an purification treatment. The reaction formation mechanisms and the products were predicted with the FactSageTM thermochemical simulation program. Different conditions were tested to determine the optimum synthesis parameters. MCS was conducted at stoichiometric ratios and different milling durations, using excess reactant amounts over the determined optimum time. After MCS, unwanted phases were removed by HCl acid leaching. Detailed phase analyses of the final powders were obtained by X-ray diffractometer (XRD), whereas detailed microstructure characterization was conducted by scanning electron microscope/energy dispersion spectrometer (SEM/EDS), transmission electron microscope (TEM) and particle size analyzer. Among the utilized parameters, the ideal composition chosen for Mo boride synthesis was 6 h milled and leached MoO3-100 wt% B2O3-50 wt% Mg (1.41 mu m), including alpha-MoB, beta-MoB, MoB2, Mo2B, Mo2B5, and Mo phases. For the synthesis of W boride, the proper composition was found as WO3-100 wt% B2O3-50 wt% Mg (0.37 mu m) containing W2B5, WB, beta-WB, WB4, W2B, and W phases after milling for 20 h and leaching. Besides, as a result of the oxidation resistance measurements at 700 and 800 degrees C, phases belonging to MoO2 and WO2 were found along with boride phases.
Citation - WoS: 2
Citation - Scopus: 2
Effect of Reinforcement Amount on the Microstructural and Mechanical Properties of Mechanically Alloyed Graphene Nanoplatelet Reinforced Al-3.5 Wt% Cu Composites
(Elsevier Science, 2025) Mertdinç-Ülküseven, Sıddıka; Süzer, İlayda; Ürper, Ahmet Kasım; Çelik, Alper İbrahim; Bacı, Doruk Tuncer; Gürarslan, Kerem Alper; Ağaoğulları, Duygu; Öveçoğlu, M. Lütfi
In this study, various amounts (0.25, 0.5, 0.75, 1, and 2 wt%.) of graphene nanoplatelets (GNPs) reinforced Al-3.5 wt% Cu metal matrix composites were produced using powder metallurgy processes consisted mechanical alloying and pressureless sintering. To compare the properties of the sintered composites, as-blended and 4 h mechanically alloyed powders were sintered to yield Al-3.5 wt% Cu matrix alloys. The microstructural, thermal and mechanical properties were examined using relevant characterization techniques. The formation of Al2Cu phase was detected at all XRD patterns of the sintered samples other than matrix and reinforcement phases. Mechanically alloyed powders exhibit the equiaxed particle morphology compared to the as-blended ones, their mechanical properties were found better than as-blended and sintered samples. Additionally, mechanical alloying led to the dispersion of GNP reinforcements into the AlCu matrix. The highest hardness value (around 153 HV) was obtained for 2 wt% GNP reinforced composite. The highest wear resistance was recorded for 1 wt% GNP reinforced composite with 2.07 +/- 0.2 mm(3)/N.mx10(-3) wear rate. Additionally, composites' compressive strength improved with adding 1 wt% GNP (similar to 68.5 MPa). The good dispersion of the optimum amount of GNP's via mechanical alloying provide to obtain preferable mechanical properties.