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Article Citation - WoS: 8Citation - Scopus: 9First-principles studies of Tin+1SiNn (n=1, 2, 3) MAX phase(Taylor & Francis Ltd, 2020) Surucu, Gokhan; Gullu, Hasan Huseyin; Candan, Abdullah; Yildiz, Bugra; Erkisi, AytacIn this study, the structural, electronic, mechanical, lattice dynamical and thermodynamic characteristics of ( 1, 2 and 3) phase compounds were investigated using the first principle calculations. These ternary nitride compounds were found to be stable and synthesisable, and the results on the stability nature of them were also evaluated for the possible and phases. -was found to be the most stable one among these new class of layered phases for which limited works are available in the literature. The band structures, that are essential for the electronic properties, were determined along with the partial density of states (PDOS) indicating the metallic behaviour of these compounds. The polycrystalline elastic moduli were calculated based on the single-crystal elastic constants and the mechanical stabilities were verified. Some basic physical parameters, such as bulk modulus, shear modulus, Young's modulus, Poisson's ratio, Debye temperature, and sound velocities, were also predicted. Furthermore, the anisotropic elastic properties were visualised in three dimensions (3D) for Young's modulus, linear compressibility, shear modulus and Poisson's ratio as well as with the calculation of the anisotropic factors. - phase showed the most isotropic characteristics with minimum deviations. These theoretical values were also used to identify the stiffness and ionic characteristics. The phonon dispersion curves and corresponding PDOS indicated that compounds were dynamically stable. Moreover, thermodynamic properties obtained from phonon dispersion curves were investigated in detail.Article Citation - WoS: 2Citation - Scopus: 2Assessment of Tensile Properties of Cast High Mg Containing Al-Mg Aluminum Alloy With Correlation of Computed Tomography Scans and Optical Crack Surface Analysis(Springer int Publ Ag, 2023) Gul, K. Armagan; Dispinar, Derya; Kayali, E. Sabri; Aslan, OzgurIn the casting of aluminum alloys, melt cleanliness has been crucial to achieve desirable final properties. Alloying elements, casting method and degassing procedures have been applied to obtain an internal structure free from defects. Most common defects have been double oxide metal films called bifilms. These defects have been detrimental to mechanical properties. Efforts in industry and academia have focused on removing those defects. Reduced pressure test (RPT) and optical evaluation of cross section of specimens have been the most preferred method of bifilm index evaluation method to assess melt quality. As this method is 2D cross-section analysis, there has not been a direct method to correlate mechanical properties with 3D volume analysis of both RPT and tensile specimens. Computed tomography scanning/imaging has been a promising and emerging method for 3D internal structure evaluation to evaluate internal defects. Subsequent mechanical properties fluctuation in correlation with defect quantity and size may be built in this methodology. In the present study, casting of aluminum alloys with high magnesium content and different alloying elements has been done. Effect of melt quality and defect quantities on internal structures have been investigated via RPT tests and computed tomography scans (CTS). Correlation of CTS and tensile tests has been shown. Tensile test specimen surfaces have been investigated via optical imaging, and bifilm effects have been shown. Alloy quality correlations with tensile tests have been established.Article Citation - Scopus: 5Evaluation of Mechanical Properties of Bi12sio20 Sillenite Using First Principles and Nanoindentation(Taylor and Francis Ltd., 2021) Isik,M.; Surucu,G.; Gencer,A.; Gasanly,N.M.The mechanical and anisotropic elastic properties of Bi12SiO20 (BSO) were investigated using density functional theory (DFT) calculations and nanoindentation. The calculated and experimentally observed XRD patterns of the compound were reported and the crystal structure of the BSO was determined to be cubic with the lattice constant of a = 1.025 nm. The second-order elastic constants and related polycrystalline elastic moduli (e.g. shear modulus, Young’s modulus, Poisson’s ratio, linear compressibility and hardness) were calculated. The calculated elastic constants indicated that BSO is mechanically stable and exhibits anisotropic characteristics. Moreover, the directional dependencies of sound wave velocities were investigated in three dimensions. Pressure-dependent bulk modulus was plotted at temperatures between 0 and 800 K. Hardness and Young’s modulus were also determined by performing nanoindentation experiments on (222) and (631) planes of the BSO single crystal. The analyses of the experimental nanoindentation data resulted in hardness and Young’s modulus values of 7.2 and 97.0 GPa, respectively. The results of DFT and nanoindentation were discussed throughout the paper. The results of the present paper would provide valuable information on the mechanical behaviours of the BSO for the optoelectronic device applications. © 2021 Informa UK Limited, trading as Taylor & Francis Group.Article Citation - WoS: 2Integrating Theoretical and Experimental Approaches To Unveil the Mechanical Properties of Cusbse2 Thin Films(Iop Publishing Ltd, 2024) Surucu, Ozge; Gencer, Aysenur; Usanmaz, Demet; Parlak, Mehmet; Surucu, GokhanAn exhaustive investigation of the mechanical characteristics of CuSbSe2 thin films is conducted in this study by combining experimental nanoindentation methods with theoretical simulations. The Ab-initio Molecular Dynamics (AIMD) calculations are performed with the machine learning (ML) force fields. By employing the Vienna Ab-initio Simulation Package (VASP) based on Density Functional Theory (DFT), theoretical inquiries are carried out to identify crucial parameters, such as bonding characteristics, elastic constants, hardness, bulk modulus, shear modulus, Young's modulus, and Poisson's ratio. Experimental validation is conducted using nanoindentation to investigate load-dependent hardness and Young's modulus in a manner that closely matches the theorized predictions. The anomalies between experimental and theoretical outcomes are ascribed to anisotropic behavior and grain boundaries. Furthermore, an investigation is conducted into the directional dependence of sound wave velocities in the CuSbSe2 films, leading to the revelation of intricate elastic property details. By employing an integrated theoretical-experimental approach, the present attempt not only increases the knowledge concerning CuSbSe2 films but also fortifies the relationship between theory and experiment, thereby bolstering the dependability of our results. The insights provided as a result of this paper facilitate the development of CuSbSe2 film applications in a variety of technological fields in the future.
