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Öğe Effects of natural hard shell particles on physical, chemical, mechanical and thermal properties of composites(SAGE Journals, 2021-05-31) Çelik, Yahya Hışman; Çelik, Kadir Serdar; Kılıçkap, ErolShelled herbal foods are widely consumed. The evaluation of the shells of these foods is important due to their features such as low cost, ease of recycling and environmental friendliness. In this study, hazelnut shell (HS), pistachio shell (PS), and apricot kernel shell (AKS) were brought to powder particles by grinding to dimensions of 300–425 µm. Some of the powder particles were converted into ash at 900°C. The amounts of cellulose, ash, humidity, and metal in these particles via chemical analyses were determined, while their structural properties via X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FT-IR) analyses. Composite materials were produced by adding 15 wt.% to the polyester matrix material from these powder particles and ashes. Compression strength, hardness, specific weight, and thermal conductivity of these composites were analyzed. The lowest and highest humidity, ash, cellulose, hemicellulose, and lignin ratios in powders showed differences depending on the type of powders. The amount of Sn and K in the HS, PS, and AKS powders were close to each other, while the amount of Ca, Na, Mg, Fe, Mn, Cu, Zn and Si was higher in AKS powder. The reinforcement adding to the polyester increased the compression strength, hardness, specific weight and thermal conductivity properties.Öğe Numerical investigation of fatigue behaviors of non-patched and patched aluminum pipes(Hibetullah KILIÇ, 2021-06-01) Adin, Hamit; Yıldız, Bilal; Adin, Mehmet ŞükrüIn this study, the fatigue behaviors of non-patched and patched aluminum pipes were investigated numerically. The Finite Element Method was used for fatigue analysis in the study. Finite Element Method was implemented with Ansys Workbench (15.0) program. Al 6063 type aluminum pipe, DP-460 type adhesive and [0/90]2 reinforced angled glass-epoxy composite patch material were used in the analyzes. As a result of the numerical study, it was observed that patch size is an effective parameter in fatigue strength and that quarter-circle and semi-circular composite patches increase the fatigue life. It was also observed in the analyzes that the quarter-circle patched aluminum pipes achieved higher fatigue strength.Öğe TM yöntemi ile üretilmiş Al matrisli kompozitlerde presleme basıncının ve B4C oranının sertlik ve aşınma davranışı üzerine etkisi(Fırat Üniversitesi, 2018-03-01) Çelik, Yahya Hışman; Kılıçkap, Erol; Yenigün, BurakToz metalürjisi (TM) yöntemi sayesinde metal tozlarının istenilen şekle çok kısa zamanda dönüştürülmesi ekonomik anlamda seri imalatı mümkün kılmaktadır. Bu durum, malzemelerde talaşlı işleme ihtiyacını ortadan kaldırarak karmaşık ve boyutsal hassasiyeti yüksek olan parçaların üretilmesine olanak sağlamaktadır. Özellikle alüminyum ve alaşımları, ticari alanlarda vazgeçilmez malzemeler olarak TM yöntemi ile üretimde yerini almıştır. Bu çalışmada, TM yöntemiyle üretilmiş B4C takviyeli Al matrisli kompozitlerin farklı presleme basıncına (400 ve 475 MPa) ve takviye oranına (takviyesiz ve ağırlıkça % 4, 8 ve 12 takviyeli) bağlı olarak mikroyapı, sertlik ve aşınma davranışları incelenmiştir. Numunelerin aşınma deneyleri özel olarak imal edilen test düzeneği ile 0,50 m/s sabit kayma hızında, farklı uygulama yüklerinde (5, 10 ve 15 N) ve farklı kayma mesafelerinde (250, 500 ve 750 m) yapılmıştır. Ayrıca üretilen kompozitlerin mikroyapısal değişimlerini belirlemek için optik mikroskop ve SEM görüntüleri incelenmiştir. Deneysel çalışmalar sonucunda, kompozit numunelerde presleme basıncının ve takviye oranının artması ile sertlik değerlerinin arttığı ve aşınma kayıplarının azaldığı tespit edilmiştir. Ayrıca kayma mesafesi ve uygulanan yükün artması ile aşınma miktarının arttığı görülmüştürÖğe Investigation of wear behavior of aged and non-aged SiC-reinforced AlSi7Mg2 metal matrix composites in dry sliding conditions(SpringerLink, 2020-01) Çelik, Yahya Hışman; Kılıçkap, Erol; Demir, Mehmet Emin; Kalkanlı, AliMetal matrix composites (MMCs) with their splendid mechanical properties have been specifcally designed for use in felds such as aerospace and aviation. The presence of hard ceramic particles in MMC increases the hardness of the matrix product and decreases its coefcient of friction. Therefore, the wear resistance is improved. Moreover, the mechanical properties of these composite materials can be improved by applying heat treatments. In this study, AlSi7Mg2 MMCs with 15 wt% SiC reinforcement were produced by squeeze casting technique. Some of the composites were aged by heat treatment. Hardness values of aged and non-aged composites were compared. In addition, abrasive wear behaviors of these composites were investigated on pin-on-disk device, depending on the load (7, 12 and 17 N), the sliding speed (0.2, 0.3 and 0.4 m/s) and the sliding distance (700, 1000 and 1300 m). Worn surfaces were also analyzed by scanning electron microscopy (SEM). As a result of the analyses, it was determined that both the hardness values and the wear resistance were higher in the composites subjected to aging treatment. Furthermore, it was observed that the increase in the applied load led up to the weight loss. The increase in the sliding distance increased both friction coefcient and weight loss. The increase in sliding speed also made way for the friction coefcient but ensured less weight loss. When SEM images were examined, it was ascertained that deformation and tribo-surface formation had a signifcant efect on weight losses.
