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Öğe Bronz ve dökme demir talaşlarının geri dönüştürülmesiyle prizmatik şekilli makine elemanı üretimi ve mekanik karakterizasyonu(2018) Aslan, Abdullah; Salur, Emin; Aydın, Güneş; Şahin, Ömer Sinan; Karadağ, Hakan Burak; Akdemir, AhmetBu çalışmada küresel grafitli dökme demir (GGG-40) ve Bronz (CuSn10) talaşlarının izostatik sıcakpresleme yöntemiyle geri dönüştürülmesi ile üretilen metal matrisli kompozit malzemelerin (MMK) üretimive mekanik davranışları incelenmiştir. MMK malzemeler 4 farklı karışım oranında 3 farklı sıcaklıkta ve 3farklı basınçta üretilerek üretim parametrelerinin gözeneklilik, sertlik ve eğilme mukavemeti üzerine etkisiincelenmiştir. Prizmatik geometrili olarak üretilen numunelerin öncelikle gözeneklilik ve yoğunluk değerleritespit edilmiştir. Daha sonra Brinell ve Mikro Vickers ve 3 noktadan eğilme deneyleri ile MMKmalzemelerin mukavemeti belirlenmiştir. Optik mikroskopi tekniği ile mikro yapı görüntüleri incelenerektalaşların birleşme mekanizması incelenmiştir. Ayrıca XRD analizi aracılığıyla metalik talaşlar arasında arafaz oluşumu olup olmadığı sorgulanmıştır. Gözeneklilik deneyleri neticesinde %20 mertebelerindegözeneklilik elde edilmiştir. Aşırı plastik deformasyon gösteren CuSn10 sebebiyle mukavemeti artanCuSn10 talaşları sertlik değerini Bulk CuSn10 ile kıyaslanabilir seviyelere getirmiştir. Eğilme deneyineticesinde MMK malzemelerin eğilme mukavemetleri bulk CuSn10’dan düşük çıkmıştır. Sonuç olarakmetal talaşların başarılı bir biçimde metal matris kompozit haline getirilebileceği gösterilmiştir.Öğe Dispersion mechanism-induced variations in microstructural and mechanical behavior of CNT-reinforced aluminum nanocomposites(Springernature, 2022) Dogan, Kemal; Ozgun, Muhammed Ihsan; Subutay, Halit; Salur, Emin; Eker, Yasin; Kuntoglu, Mustafa; Aslan, AbdullahThe combination of powder metallurgy and ball milling method has been widely regarded as the most beneficial route for producing multi-walled carbon nanotubes (MWCNTs)-reinforced aluminum matrix composites. In this study, the effects of different milling times (1, 2, 4, and 8 h) on the structural, morphological, and crystallographic properties of MWCNTs-reinforced Al7075 composite powders were characterized by particle size analyzer, Raman spectroscopy, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), and X-ray diffraction (XRD). After the morphological and structural characterization of the milled powders, the microstructural and mechanical properties of the hot-pressed composites were evaluated using an optical microscope, SEM, density, and Brinell hardness measurements. Considering milled powder characterization, the MWCNTs were gradually distributed and embedded within the matrix as the milling time increased. Milling for 8 h resulted in a minimum level of particle size (11 mu m) with shortened and uniformly dispersed CNTs. Brinell hardness of the composite increased from 91 to 237 HB -a x2053;%160 after 8 h of milling. Such a remarkable increment in hardness could be attributed to several concurrent strengthening effects related to dispersion, solution, grain refinement, and Orowan looping mechanisms. However, relative density results revealed that the composite produced by 2 h milled powders exhibited the highest density (%99.96). The observed differences between hardness and density results were ascribed to powders' deteriorated packing and sintering behavior due to an increment in the hardness of particles and variation in particle size range and morphology, which resulted from following different milling protocols.Öğe The Effect of Ultrasonic Cleaning Upon Mechanical Properties of Metal Matrix Composites(Springer India, 2021) Aslan, Abdullah; Salur, Emin; Gunes, Aydin; Sahin, Omer Sinan; Karadag, Hakan Burak; Akdemir, AhmetThe aim of this study is to produce composite materials by recycling metallic chips, which are found in industry as a large amount of waste. In addition, it is aimed to investigate the effect of ultrasonic cleaning process as the consolidation behavior and mechanical properties of bulk material directly depend on the cleaning of waste metallic chips. In the present investigation, spheroidal graphite cast iron (GGG-40) was employed as reinforcement material in tin bronze (CuSn10) matrix system. GGG-40 and CuSn10 chips were cleaned by ultrasonic agitation in water for 20 and 40 min. Consolidation of the cleaned metallic chips was achieved with a hot press by applying 820 MPa pressure under 450 degrees C, and the cylindrical and prismatic metal matrix composite materials with different reinforcement ratios were successfully produced. Energy-dispersive X-ray and scanning electron microscopy analyses were carried out to determine the amount of the oxide removed from the surfaces of chips. The mechanical properties of the samples were determined by hardness, porosity, compression and three-point bending tests. According to the results of the analyses, it was found that CuSn10 surfaces were cleaned from 20%, 50% and GGG-40 surfaces from 35%, 39% oxides during 20- and 40-min cleaning time, respectively. In addition, the results of the mechanical tests revealed that increased ultrasonic cleaning time improves the consolidation quality of metallic chips and it provides successful covering of GGG-40 chips by the CuSn10 chips as a result of a better structural integrity. New machinery parts with high mechanical properties can be produced as a result of recycling of the metallic chips which are available as waste in industry by appropriate cleaning process and this situation makes this study more innovative, economical and environmentally friendly research.Öğe The effects of harsh aging environments on the properties of neat and MWCNT reinforced epoxy resins(Elsevier Sci Ltd, 2021) Aslan, Abdullah; Salur, Emin; Duzcukoglu, Hayrettin; Sahin, Omer Sinan; Ekrem, MurselIn this study, the effects of different harsh aging environments on the chemical and mechanical properties of neat and multiwall carbon nanotubes (MWCNT) reinforced epoxy resins were investigated. The neat and 1 wt% MWCNT reinforced epoxy resins were exposed to four different corrosive environments, namely deionized water, NaCl solution (10 wt% NaCl), H2SO4 solution (10 wt% H2SO4), and HCl solution (10 wt% HCl. The mass variation results revealed that the highest absorption rates were found in specimens aged in both acidic environments. The highest amount of absorption was observed in the H2SO4 environment, measured approximately 3% for neat epoxy, and 6.5% for MWCNT reinforced epoxy resin. FT-IR spectrums showed that the most affected peaks belong to specimens aged in both acidic environments. Tensile test results revealed that the aging process in H2SO4 solution and deionized water deteriorated the strength of specimens. According to the literature, it was reported that the strength of specimens aged in NaCl solution environment is decreased. However, the same trend has not been in this study. In our study, the strength of specimens aged in NaCl solution environment increased impressively by 29%, which makes this study more striking. Another important point analyzed from the tensile test results was that the MWCNT nanoparticle reinforcement adversely affects the strength of the epoxy resin. So, it can be clearly stated that the use of expensive MWCNTs as filler of epoxy resin is not useful to improve its aging resistance. The scanning electron microscope (SEM) and optical microscope images showed that acidic environments result in different fracture mechanisms from typical polymer damaged surfaces reported in available researches. (C) 2020 Elsevier Ltd. All rights reserved.Öğe Mechanical properties and microstructure of composites produced by recycling metal chips(Springer, 2018) Aslan, Abdullah; Gunes, Aydin; Salur, Emin; Sahin, Omer Sinan; Karadag, Hakan Burak; Akdemir, AhmetIn this study, the processing and mechanical properties of porous metal matrix composites (MMCs) composed of spheroidal cast iron chips (GGG40) and bronze chips (CuSn10) and formed by hot isostatic pressing were investigated. Bronze chips (CuSn10) were used as a matrix component, and spheroidal cast iron (GGG40) chips were used as a reinforcement component. The MMCs were produced with different CuSn10 contents (90wt%, 80wt%, 70wt%, and 60wt%). The hot isostatic pressing process was performed under three different pressures and temperatures. The produced MMCs were characterized using density tests, Brinell hardness tests, and compression tests. In addition, the consolidation mechanism was investigated by X-ray diffraction (XRD) analysis and scanning electron microscopy. The test results were compared with those for bulk CuSn10 and bulk GGG40. Mechanical tests results revealed that the metallic chips can be recycled by using hot pressing and that the mechanical properties of the produced MMCs were similar to those of bulk CuSn10. XRD and microscopy studies showed that no intermetallic compounds formed between the metallic chips. The results showed that the CuSn10 and GGG40 chips were consolidated by mechanical interlocking.
