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.

Onur Kazım Ateş

Metalik malzemelere kıyasla daha düşük ağırlığa sahip olan yüksek performanslı polimer kompozit malzemeler; otomotiv, havacılık ve kimya endüstrisinde, çalışma koşullarındaki mühendislik uygulamalarında yapısal malzeme olarak yaygın şekilde kullanılmaktadır. Ekonomik verimlilik ve güvenliğin sağlanması için düşük özgül ağırlık, benzersiz mekanik ve tribolojik özellikler ve bozulmaya karşı yüksek direnç sağlanması gerekmektedir. Polimer matrisine homojen olarak ilave edilen nano veya mikro boyutlu inorganik parçacıklar hafif ve dayanıklı kompozit malzemelerin üretimine katkı sağlamaktadır. Bu çalışmada, cam elyaf kumaş kullanılarak, Hexion Epikote Resin MGSLR 635\Hexion Epikure Curing Agent MGH LH 635 epoksi reçine sistemi ile el yatırma yöntemi uygulanarak farklı oranlarda nano-grafen parçacık takviyeli polimer kompozit malzemeler üretilmiştir. Matrise ağırlıkça % 0.2, % 0.4, % 0.6, % 0.8 ve %1 oranlarında nano-grafen parçacıkları eklenerek çekme ve üç nokta eğme testleriyle nano-grafen takviyesinin mekanik özellikleri üzerindeki etkisi araştırılmıştır. Çekme ve üç nokta eğme testleri sonucunda, ağırlıkça artış miktarına paralelel olarak nano-grafen takviyeli polimer kompozitlerin çekme mukavemet değerlerinin artmasının aksine eğme mukavemet değerlerinin azaldığı görülmüştür. Anahtar Kelimeler: Çekme, Eğme, Grafen, Kompozit, Nano

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.