Yazar "Gungor, Ali" seçeneğine göre listele

Listeleniyor 1 - 7 / 7
  • Küçük Resim Yok
    Öğe
    Biocorrosion and Mechanical Properties of ZXM100 and ZXM120 Magnesium Alloys
    (Springer International Publishing Ag, 2019) Incesu, Alper; Gungor, Ali
    In this study, as-cast Mg, ZXM100 (1.07Zn-0.21Ca-0.31Mn) and ZXM120 (1.01Zn-1.63Ca-0.30Mn) alloys were produced by gravity die casting method, and microstructure, phase analysis, corrosion and mechanical properties of the alloys were investigated comparatively in order to develop degradable Mg-based biomaterials with improved properties. It is observed that Ca2Mg6Zn3 phase is expected to be present in ZXM100 (1.07Zn-0.21Ca-0.31Mn) alloy totally dissolved in the alpha-Mg matrix after homogenization heat treatment. However, Mg2Ca phase is expected to be present in ZXM100 (1.07Zn-0.21Ca-0.31Mn) alloy partially dissolved in the alpha-Mg matrix. Results showed that ZXM100 alloy has a much more homogeneous structure, a better performance, higher corrosion resistance and mechanical properties than those of as-cast Mg and ZXM120 alloy. ZXM100 (0.099 mm/year) alloy has a three times slower corrosion rate than ZXM120 (0.294 mm/year) alloy. It is found that the ZXM100 alloy has closer values to the desired corrosion rate and mechanical properties as a biodegradable implant material.
  • Küçük Resim Yok
    Öğe
    Comparison of Hot-rolled Unalloyed Magnesium and Magnesium Alloys in terms of Biodegradability and Mechanical Properties
    (Gazi Univ, 2022) Incesu, Alper; Gungor, Ali
    In this study, hot rolling is properly performed on pure magnesium and two of Zn, Ca and Mn containing magnesium alloys. Biodegradability and mechanical properties are investigated comparatively in their rolled state. While the average grain sizes of the two alloys were close to each other, it was observed that the Mg-1.01Zn-1.63Ca-0.30Mn alloy had higher hardness (61.5 +/- 0.2 HV) at hot rolled state. The lowest corrosion rate in electrochemical corrosion test on Mg-1.07Zn-0.21Ca-0.31Mn alloy is observed to be 1.772 mm/yr. As for the immersion corrosion test on the same alloy, the lowest corrosion rate is detected to be 0.054 mm/yr. Moreover, Mg-1.07Zn-0.21Ca-0.31Mn alloy has the highest tensile strength. Based on the results, it is ascertained that hot-rolled Mg-1.07Zn-0.21Ca-0.31Mn alloy possesses a better biodegradability and mechanical properties compared to hot rolled commercially unalloyed Mg and 1.01Zn-1.63Ca-0.30Mn alloy.
  • Küçük Resim Yok
    Öğe
    A composite building isolation system for earthquake protection
    (Elsevier - Division Reed Elsevier India Pvt Ltd, 2019) AlMusbahi, Salah; Gungor, Ali
    The main point of this paper is to study a new hybrid composite isolation system for the protection of structures against earthquakes. ANSYS simulation software was used for modelling and analysis. A 40-storey building with multiple degrees of freedom has been studied under seismic waves. In this study, a 40-storey structure was chosen to be retrofitted with the proposed hybrid isolation system and analysed. The building's width and height are 40 m and 160 m, respectively. In addition, the stiffness is linearly distributed. The building is studied under two different boundary conditions. In Case I, the base of the building is rigidly attached to the ground while it is retrofitted with the proposed hybrid isolation system in Case II. Two cases were considered including a rigidly supported one and another isolated one. The results show a noticeable reduction in displacement, velocity and acceleration of the stories. Based on results, displacement, velocity and acceleration of the stories remarkably reduced while the stiffness of the structure increased. In addition, the isolated case is preferred to be utilized in structure because it prevents the structure from severe damages. (C) 2018 Karabuk University. Publishing services by Elsevier B.V.
  • Küçük Resim Yok
    Öğe
    Designing and modeling U-notch fatigue sensor to predict the fatigue life of structural components
    (Elsevier - Division Reed Elsevier India Pvt Ltd, 2019) Alshahbouni, Tariq; Gungor, Ali
    Fatigue sensors are used as Structural Health Monitoring (SHM) mechanisms to detect damage on structural components before any failures occur. In this study, a U-notched fatigue sensor was designed and analyzed to predict the fatigue life before catastrophic failure occurs. The ANSYS workbench software and 7075-T6 aluminum alloy were used to model and analyze our U-notch type fatigue sensor. The sensor model consisted of four beams of 305 x 76.2 x 1.6 mm (length x width x thickness) dimensions with different fatigue U-notch radii. It was observed that fatigue life increased with an increase in the U-notch radius. However, the value of the maximum equivalent stress decreased with an increase in the notch radius. In addition, fatigue damage occurred around the U-notch radius when the U-notch radius was equal to or less than 6.4 mm. (C) 2018 Karabuk University. Publishing services by Elsevier B.V.
  • Küçük Resim Yok
    Öğe
    Fatigue v-notch sensor for monitoring the health of critical structures
    (Elsevier - Division Reed Elsevier India Pvt Ltd, 2019) Hadyia, Ahmed; Gungor, Ali
    The principal points of this paper include describing the design, suggesting improvements in the V-notch sensors, evaluating stresses to predict the failure of critical components (such as bridge ways) by using ANSYS simulations to estimate the stresses through V-notch geometry passive sensors with different depths in the structure. The sensor developed in this study consists of six beams with opposite edge V-notches that have been designed parallel to the applied tension load of a steel structure. When the offset value lies in the range of 3.2e-2 mm, it decreases the value of the Von-Mises stress after this point of up to 0.214e10 Pa while the displacement value reaches up to 7.824e-2 mm. These results are linked to different V-notch parameters, including angle orientation, notch depth, mechanical properties, boundary conditions and applied tension loads, which show that the Von-Mises stress increases with the increasing load ratio. In addition, the increase in the number of sensor arms in the present configuration can accommodate additional notches, which possibly tends to lower stress ranges with more loading cycles. (C) 2018 Karabuk University. Publishing services by Elsevier B.V.
  • Küçük Resim Yok
    Öğe
    Mechanical properties and biodegradability of Mg-Zn-Ca alloys: homogenization heat treatment and hot rolling
    (Springer, 2020) Incesu, Alper; Gungor, Ali
    In this study, Mg was alloyed with Zn and Ca to produce six different Mg-Zn-Ca alloys (designated as ZX alloys) by the gravity die casting method. Zn contents of the alloys were 1 wt., 3 wt., and 5 wt.% and Ca contents of the alloys were 0.2 wt. and 1.8 wt.%. Homogenization heat treatment was applied to all cast alloys. After that, a part of each homogenization heat-treated alloys was hot-rolled. Microstructure, mechanical properties, electrochemical and immersion corrosion behaviors at simulated physiological conditions of the heat-treated and hot-rolled alloys were compared. Increasing the amount of alloying elements (Zn and Ca) in Mg reduces grain size and improves the hardness. It was seen that the microstructure consisted of alpha -Mg as a matrix phase and intermetallic phases: Mg2Ca phase for the alloy having Zn/Ca=0.37 (ZX12) and Ca2Mg6Zn3 phase for the other alloys. When the mechanical properties and corrosion rates of homogenized and hot-rolled alloys were compared, it was seen that hot-rolled ZX10-h (Mg-0.94Zn-0.16Ca) alloy can be considered as a fracture bone fixation plate material with its acceptable properties: 1212.1MPa yield strength, 2263.7MPa tensile strength, % 4.1 +/- 0.2 elongation, and 0.062mm/year immersion corrosion rate.
  • Küçük Resim Yok
    Öğe
    Phase selection and mechanical properties of permanent-mold cast Mg-Al-Ca-Mn alloys and the role of Ca/Al ratio
    (Elsevier Science Sa, 2018) Elamami, Hamid Ali; Incesu, Alper; Korgiopoulos, Konstantinos; Pekguleryuz, Mihriban; Gungor, Ali
    In this work, phase selection, microstructure and mechanical properties of Mg-Al-Ca-Mn alloys with three different Ca/Al ratios (0.58, 0.79 and 0.91) were studied. The Mn content of the alloys was kept constant at similar to 0.30 wt%. Thermodynamic non-equilibrium (Scheil) simulations, X-Ray Diffraction (XRD) analyses and Scanning Electron Microscopy/Electron Dispersive Spectroscopy (SEM/EDS) determined that all three alloys contain alpha-Mg solid solution phase, Al8Mn5 intermetallics and, depending on the Ca/Al ratio, combinations of C36-(Mg,Al)(2)Ca (hP24 a = 0.577-0.586 nm, c = 1.819-1.835 nm), binary C14-Mg2Ca (hP12, a = 0.620 nm c =1.023 nm), ternary C14-Mg2Ca (hP12, a = 0.561-0.599 nm, c =1.025 -1.051 nm), and/or C15-Al2Ca (cF24, a = 0.793 nm) Laves phases. It is observed that Ca/Al ratio shows a direct relationship with the total amounts of Laves intermetallics and the amount of the C36 phase, and an indirect relationship with the amount of C14 phase. Microhardness measurements, room and elevated temperature (150 degrees C and 200 degrees C) tensile tests, as well as tensile creep tests (175 degrees C/50 MPa), were carried out to determine the mechanical properties of the alloys. Results show that the hardness and room temperature yield and ultimate tensile strengths (UTS) increase while the ductility at all temperatures decreases with increasing Ca/Al ratio. At elevated temperatures, in the range of Ca/Al ratios investigated, the UTS has a relationship with the dissolved amount of Ca and Mn in the alpha-Mg phase. Creep strain was found to decrease from 0.35% to 0.05% as Ca/Al increases from 0.6 to 0.9 and as the amount of the C36 phase which can strengthen grain boundaries increases. One order of magnitude improvement seen in creep resistance as the Ca/Al ratio increases from 0.6 to 0.8 is attributable to the presence of C36 and C14 phases rather than C36 and thermally unstable C15 phase in the alloys and to the increased amounts of dissolved Mn and Ca in the a-Mg matrix. (C) 2018 Elsevier B.V. All rights reserved.