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Öğe Hardness and wear behaviours of al matrix composites and hybrid composites reinforced with B 4 C and SiC(Springer Nature, 2019-01-15) Çelik, Yahya Hışman; Kılıçkap, ErolThe conversion into the desired shape of the metal powders using Powder Metallurgy (PM) method enables economically mass productions. This case allows producing parts with complex and high dimensional accuracy with no machining. In this study the composites and hybrid composites with Al matrix were produced using PM method with different ratios B4C and SiC. Microhardness and wear experiments of the produced composites were investigated. Wear experiments were performed at a constant speed of 0.5 m/s, application loads of 5, 10 and 15 N and sliding distances of 250, 500, and 750 m. Then, SEM images of composites and hybrid composites were captured. The increase of the reinforcement ratio in the composites contributed to the increase of the hardness. The highest hardness value was computed as 58.7 HV from 16% B4C reinforced composite. In addition, the increase in the reinforcement ratio contributed to the increase of the wear resistance. The increase in the load and sliding distance also increased the wear. The minimum weight loss was calculated as 18 mg from 5 N load, 250 m sliding distance and 16% SiC reinforced composite.Öğe Investigation of microstructure, hardness values and compressive strengths of SiC/Al composites in different reinforcing rates produced by PM method(Fırat Üniversitesi, 2017-10) Çelik, Yahya Hışman; Kılıçkap, ErolIn this study, the microstructures, hardness values and compressive strength of SiC reinforced Al metal matrix composites in different rates produced by powder metallurgy (PM) method have been examined. Al powders which has 99% purity and 1-210 µm size, and SiC powders which has 98.5% purity and 1-45 µm size were used in experiments. These powders were weighed in proportions pure Al, 4% SiC/Al, 8% SiC/Al, 12% SiC/Al, 16% SiC/Al via precision balance. A mechanical mixing device was used in order to homogeneously mix of the weighed powders. These mixtures were pressed under pressure of 475 MPa. All pressed materials were made into composite by sintering for 120 minutes at 580 ºC. Microstructures, hardness values and compressive strength of the composites were analyzed by polishing the surfaces of the composites. As a result of analysis, it was observed that the SiC reinforces were uniformly dispersed in Al matrix, the hardness values of the composite increased with increasing reinforcement rate and the compressive strength values of the composites were similar to one anotherÖğe 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 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 görülmüştür
