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Sürdürülebilir Kalkınma Amaçları

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• MakaleAçık Erişim2026/r/gumushane/12264
  Dynamic and Mechanical Properties of Nanoparticle Doped Aramid/Glass Fiber Reinforced Interply Hybrid Composites

  Sadik, Ayşegül Cansu; Karabudak, Filiz; Kula, Muhammed Emin

  In this study, the mechanical and dynamic properties of glass/aramid interply hybrid composites reinforced with four different nanoparticles were investigated. Firstly, matrix modification was performed and composite plates were manufactured by hand lay-up technique. Silicon dioxide (SiO2), graphene (GNP), silver (Ag) and cerium oxide (CeO2) nanoparticles were added to the epoxy matrix as reinforcement. With the addition of nanoparticles, the highest tensile (16%) and flexural (67.3%) strengths were observed in Ag reinforced composites. Tensile (16.8%) and flexural (14.4%) strengths decreased with the addition of graphene nanoparticles. Tensile and flexural tests revealed delamination, matrix and fibre rupture in all plate types. As a result of modal analysis, the highest natural frequency values and the lowest damping ratios were determined in the FFBC boundary condition. The addition of nanoparticles improved the mechanical properties of the composites in general.

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• MakaleAçık Erişim2026/r/gumushane/12135
  Comparative Mechanical and Thermal Performance of Graphene- and Silver Nanoparticle-Reinforced PLA Fabricated by FDM 3D Printing

  Karabudak, Filiz

  The increasing demand for high-performance and multifunctional polymer materials has driven interest in improving the mechanical properties of polymer components produced through additive manufacturing. This study aims to systematically investigate and comparatively evaluate the effects of low-content nanofiller incorporation on the structural, thermal, and mechanical performance of PLA-based materials produced via fused deposition modeling (FDM), with a focus on identifying filler-dependent behavior under different loading conditions. In this study, polylactic acid (PLA) composites reinforced with 0.5 wt.% graphene (Gr) and 0.5 wt.% silver (Ag) nanoparticles, added separately, were produced using fused deposition modeling (FDM) and comparatively investigated. Each nanofiller was incorporated individually into PLA-based filaments, and standard test specimens were fabricated via 3D printing. Structural, thermal, and mechanical properties were evaluated using tensile, compressive, and three-point bending tests, along with SEM, EDS, XRD, FTIR, DSC, and TGA analyses. The results showed that pure PLA exhibited typical brittle behavior and a single-stage thermal degradation profile. The tensile strength of pure PLA was 41.93 MPa, and the flexural strength was 70.76 MPa. The addition of 0.5 wt.% graphene led to noticeable improvements, particularly in flexural properties, while only a minimal (almost negligible) increase was observed in tensile strength, with tensile strength increasing to 42.24 MPa (+0.74%) and flexural strength increasing to 110.78 MPa (+56.6%). In contrast, 0.5 wt.% Ag exhibited mixed and load-dependent mechanical behavior, with slight improvements in flexural strength but reductions in tensile and compressive properties, where tensile strength decreased to 22.13 MPa (−47.2%) while flexural strength increased to 112.06 MPa (+58.3%). Structural and thermal analyses indicated that both nanofillers did not significantly alter the PLA matrix chemically, while contributing to controlled changes in material properties primarily through physical interactions. The novelty of this work lies in the comparative evaluation of graphene and silver nanoparticle reinforcement at a fixed low loading level within FDM-processed PLA, combined with a comprehensive and correlated analysis of mechanical, structural, and thermal behavior on the same specimen sets, enabling a clearer understanding of filler-dependent performance mechanisms in additively manufactured nanocomposites. Overall, it was concluded that low-rate nanofiller additions, when properly dispersed, may lead to selective improvements in the performance of PLA-based composites depending on filler type and loading mode, and show potential for advanced engineering applications such as lightweight structural components, functional sensors, and additive-manufactured parts requiring tailored mechanical performance and multifunctionality.

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• MakaleAçık Erişim2025/r/gumushane/19731
  Investigation of mechanical properties of nano-graphene reinforced polymer composites

  Karabudak, Filiz; Ateş, Onur Kazım; Zamanlou, Hamid

  The demand for lightweight and durable materials in industries such as automotive, aerospace, and chemical engineering has driven research into advanced composite materials. This study investigates the interaction between nano-graphene and polymer matrices, focusing on how varying concentrations of nano-graphene can optimize mechanical properties and potentially revolutionize the design of structural components. Polymer composite materials were produced using glass fiber fabric and an epoxy resin system employing the hand lay-up method. Nano-graphene was incorporated into the matrix at weight percentages of 0.2%, 0.4%, 0.6%, 0.8%, and 1%.Notably, the addition of 1% nano-graphene resulted in a significant tensile strength increase, achieving a maximum value of 186.73 MPa, compared to the control group at 53.71 MPa. This enhancement is attributed to the improved stress transfer mechanisms facilitated by the nano-graphene’s high surface area and exceptional mechanical properties. However, an unexpected decrease in bending strength was observed, with the glass fiber control group composites exhibiting the highest bending strength of 404.75 MPa. This trend suggests that while nano-graphene enhances tensile properties, it may introduce interfacial weaknesses or disrupt fiber alignment in bending scenarios. These findings reveal the complex nature of nano-graphene reinforcement, emphasizing the need for tailored formulations to balance tensile and bending performance. Further investigation into the interfacial bonding and distribution of nano-graphene within the polymer matrix is warranted to develop optimized composite materials for structural applications.

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• MakaleAçık Erişim2025/r/gumushane/14237
  Investigation of Tensile and Fatigue Behavior of Cr/CrN/TiCrN/TiCrCN Multilayer Films Coated on AA6063 and AZ91 Alloys by Closed-Field Unbalanced Magnetron Sputtering Process

  Yeşildal, Ruhi; Sezer, Sadberk; Karabudak, Filiz

  Despite the widespread use of Mg and Al alloys among light metals in the automobile and aviation industries, they have low tensile and fatigue strength. Therefore, in the present work, AZ91 Mg and AA6063 Al alloys were coated with a multilayer transition metal nitride film (Cr/CrN/TiCrN/TiCrCN) to increase fatigue and tensile strength. Films with Cr/CrN/TiCrN/TiCrCN microstructure architecture were synthesized on the surfaces of AZ91 Mg and AA6063 Al alloys using the CFUBMS (closed-field unbalanced magnetron sputtering) system, one of the PVD (physical vapor deposition) techniques. Films’ structural properties were analyzed by XRD, SEM, and EDAX, whereas mechanical properties were investigated using tensile and rotary bending fatigue testing machines. According to the SEM examination, the Cr, CrN, TiCrN, and TiCrCN multilayer nitride films on the two alloys have a columnar and dense microstructure. The XRD analysis detected Cr (211), CrN (111) and (200), TiN (111), (200) and (222), and TiCN (200) and (311) diffraction peaks. The Cr/CrN/TiCrN/TiCrCN multilayer coating increased the fatigue limit value of AZ91 by 11.22% from 70.26 MPa to 78.15 MPa. The fatigue limit value of AA6063 decreased by 9.79% from 79.71 MPa to 71.9 MPa. After coating, the tensile strength value of AZ91 increased from 137.89 MPa to 139.65 MPa, while the tensile strength of AA6063 decreased from 129.35 MPa to 118.16 MPa.

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• MakaleAçık Erişim2025/r/gumushane/12526
  Corrosion and structural properties of lightweight magnesium and aluminum alloy cores based sandwich composites

  Keleş, Abdulsamet; Karabudak, Filiz; Acar, Volkan; Kula, M. Emin; Aslan, Mustafa; Karabacak, A. Hasan; Alibeyoğlu, Fatih

  Metal plate core-based sandwich composites have the potential to revolutionize various industrial fields due to their mechanical strength and vibration damping. In this study, AZ91 (a magnesium alloy) and Al1050 (an aluminum alloy) metal core-based sandwich composites of AZ91/carbon fiber-epoxy, AZ91/glass fiber-epoxy, Al1050/carbon fiber-epoxy, and Al1050/glass fiber-epoxy sandwich composites were manufactured. These composites' mechanical and dynamic properties were determined through tensile, three-point bending, and vibration tests. AZ91-reinforced carbon fiber composites exhibited a 28.8% higher tensile strength than glass fiber composites, while Al1050-reinforced carbon fiber composites showed a 17.2% higher tensile strength performance than glass fiber composites. Moreover, AZ91 reinforcement led to composites with higher average flexural strength for both fibers. In vibration tests conducted under clamped and free-free boundary conditions, the highest first natural frequency was observed in AZ91/carbon fiber samples, sparking further interest. Conversely, the highest first damping ratio was observed in Al1050/glass fiber specimens. In addition, the corrosion behavior of sandwiches was evaluated, and it was found that glass fiber provided better corrosion resistance than carbon fiber. Highlights: Sandwich composites comprising AZ91/Al1050 cores and carbon/glass fiber reinforced epoxy face sheets were manufactured. Galvanic corrosion effects were evaluated, and glass fiber was found to provide higher corrosion resistance. AZ91/carbon fiber sandwich showed 28.8% higher tensile strength than glass fiber. Vibration tests revealed the AZ91/carbon fiber sandwich had the highest first natural frequency. Al1050/glass fiber sandwich exhibited the highest first damping ratio.

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• MakaleAçık Erişim2024/r/gumushane/14123
  Fatigue and tensile behaviour of Ti+TiN+Ti+TiVN multilayer nitride films coated on AZ91 magnesium alloy by closed field unbalanced magnetron sputtering

  Alibeyoğlu, Fatih; Karabudak, Filiz; Yeşildal, Ruhi; Balcı, Arif; Efeoğlu, İhsan; Ateş, Onur Kazım

  Despite their extensive use in the automotive and aerospace industries, Mg and Mg alloys, which are light metals, exhibit low fatigue and tensile strength. In this study, transition metal-nitride (TMN) multilayer coatings (Ti+TiN+Ti+TiVN) were coated twice on AZ91 Mg alloy using a Confined Field Unbalanced Magnetron Sputtering (CFUBMS) system to increase fatigue and tensile strength. The structural properties of the films were analyzed by using X-ray diffraction (XRD), scanning electron microscope (SEM), and energy dispersive spectrometry (EDS) methods, and the mechanical properties were analyzed by rotating bending fatigue and tensile testing machines. Ti+TiN+Ti+TiVN multilayer nitride surface coatings on AZ91 Mg alloys showed a dense and columnar microstructure and according to XRD results (111) was the preferred orientation with the dominant peak. The fatigue limit value of the AZ91 base material was fixed at 60.46 MPa, while it increased to 68.48 MPa after being coated with multilayer nitride. Along with the multilayer nitride coating, the tensile strength increased from 169.98 MPa to 175.43 MPa. As a result, the multilayer hard nitride coating with low surface roughness, which fills the defects, notches, and voids on the surface of the AZ91 base material, increased the fatigue and tensile strength in parallel. Based on the outcomes of the research, the literature has been enriched with an innovative approach through the enhancement of fatigue and tensile strengths by applying a CFUBMS coating to lightweight metals and alloys, such as AZ91, especially in the transportation industry where lightness and dynamic load resistance are essential.

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• MakaleYalnız künye2023/r/gumushane/16770
  Wear Behavior of Dental Restorative Materials

  Sen, Sadri; Zamanlou, Hamid; Karabudak, Filiz; Süküroglu, Ebru Emine

  Gradual wear of opposing teeth is a normal phenomenon in human dentition. There is a need for quality dental restorative materials to repair or replace natural teeth to ensure a higher quality of life through dental health. One of the main physiological mechanism that exists in dental materials during normal muscle function is called abrasion. There are two types of that in teeth which are common; Two-body and three-body. If the teeth are contacted directly, it is referred to as two-body abrasion. However, when there is abrasive slurry-like food between the teeth, this abrasive is called to be three-body abrasive. Several types of materials are available in current dentistry for teeth restoration and replacement, and new materials are being promoted every year. Dental specialists need to understand the wear mechanisms of these new types of dental restorative materials, alone or in combination with either enamel or other dental restorative material. The present study evaluates the abrasive resistance of three restorative materials groups: direct composites, indirect composites, and ceramics. To define the resistance of the wear, the authors then perform a micro-wear test on chosen materials. The results show that the wear mechanism is abrasive due to its low hardness compared to zirconia ball. The wear path in the nanohybrid (Grandio (R), 87s% w/w (71s% volume) inorganic nanohybrid filler, BisGMA, UDMA, TEGDMA) sample was smooth and without particles. In this study wear FEM analysis calculated for all models and the answers compared with experimental data.

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• MakaleYalnız künye2023/r/gumushane/14524
  The Effect of Surface Roughness on Fatigue Life in AZ31 Magnesium Alloy

  Karabudak, Filiz; Şüküroğlu, Ebru Emine; Şüküroğlu, Süleyman; Yeşildal, Ruhi

  Magnesium alloys have excellent properties such as high specific strength, rigidity, good damping, electromagnetic shielding, castability, and machinability. However, corrosion, creep, and fatigue resistance are generally the properties that need to be improved. In this study, a hybrid coating was formed on AZ31 magnesium alloy with different surface roughness at different frequencies. In the hybrid coating, an oxide coating was first grown on the surface by the micro-arc oxidation method, and then, the epoxy coating was grown on this oxide coating by the dipping method. The characterization of the coatings was performed by XRD, SEM, and EDS analysis. Furthermore, the relationship between fatigue life and surface roughness was also discussed in this study. The fatigue life and strength of the coated samples were determined as a result of the tests performed on the fatigue device. It was concluded that the fatigue life and strength of hybrid coatings were much better compared to uncoated and single-layer coated samples.

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• MakaleAçık Erişim2023/r/gumushane/12567
  Strength Analysis in Bonded, Bolted and Bolted-Bonded Joints, Single Lap Joints, Metal/Composite Plates

  Sadık, Ali; Karabudak, Filiz

  Today, especially in many fields that require structural durability, such as the aerospace and automotive industries, there has been a need to use different bonding techniques separately or together in order to use materials together with different mechanical properties. In this study, stress and damage analysis of single lap joints, bonding and bolt-bonding metal/composite joints under tensile loads were performed. The nine kinds of single lap joint models in different combinations (bonded, bolted and bolt-bonded) were prepared by using acrylic adhesive (Acrytron 1E1) and 100-25-3 mm in size; AZ91/AZ91, AZ91-carbon fiber and carbon fiber-carbon fiber plates. Some comparisons were carried out by examining the stresses and deformations that occur in joint models exposed to tensile and 4-point bending tests. As a result of the tensile test, it was determined that the highest maximum tensile stress occurred in AZ91-CF bolt-bonded samples. In the four-point bending test, the maximum shear force value was determined in the CF-CF bolted-bonded samples.

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• MakaleAçık Erişim2023/r/gumushane/12014
  High-cycle fatigue and tensile strength of AZ91 Mg alloy with MAO-epoxy duplex coating

  Karabudak, Filiz

  In this study, an epoxy layer was formed by the immersion process, on the oxide layer grown by the micro-arc oxidation (MAO) treatment of the AZ91 magnesium alloy, using the thin film sealing technology, and its effect on fatigue and tensile stress under high cycle conditions was investigated. The microstructures of the AZ91 base material, MAO/AZ91 and MAO-epoxy/AZ91 samples, which were subjected to high-cycle fatigue tests and uniaxial static tensile tests, were assessed through the scanning electron microscope (SEM), X-ray diffraction (XRD) mechanical tests, and fatigue and tensile tests. As a result, the MAO-epoxy duplex coating, which has a homogeneous and compact structure, was observed to improve the fatigue limit value/life, yield strength, ultimate tensile strength, and percentage elongation values of the base material significantly.

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