Akımsız Ni-B kaplı cam elyaf takviyesi ile alüminyum matriksli kompozit üretimi ve karakterizasyonu
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Dosyalar
Tarih
2021
Yazarlar
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Yayıncı
Bursa Teknik Üniversitesi
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Alümiyum ve alaşımları özellikle otomotiv ve havacılık sanayisinde vazgeçilmez bir malzeme haline gelmiştir. Takviye elemanı ile güçlendirip çeliğe göre daha hafif ama buna kıyasla daha mukavim olan Al-MMK'lerin kullanımı otomotiv ve havacılık sanayisinde artmaktadır. Bu tez çalışmasında matriks olarak A380 (EN AC 46000) alaşımı ve takviye elemanı olarak E sınıfı cam elyaf kullanılarak döküm yöntemi ile metal matriks kompozit (MMK) üretimi yapılmıştır. Çalışmanın temel konularından biri olan akımsız kaplama işleminden faydalanılmıştır. Akımsız kaplamada kullanılan temel kaplama bileşeninin ise dünya'daki oranına göre Türkiye'de yüksek rezerve sahip olan bor elementinin sanayiye kazandırılması amacıyla akımsız Ni-B yöntemi özellikle seçilmiştir. İlk olarak cam elyaflara akımsız Ni-B kaplama işlemi gerçekleştirilmiştir. Daha sonra elde edilen kaplanmış cam elyaflar iki farklı yöntem kullanılarak sıvı alüminyuma ilave edilmiştir. İlk yöntemde kaplanmış cam elyaflar pota üzerinde kepçe yardımıyla sıvı alüminyum içerisine ilave edilerek karıştırılmıştır. Diğer yöntemde ise karıştırma yapılmadan sıvı alaşım ve Ni-B kaplı cam elyaflar kokil kalıba eş zamanlı beslenmiştir. Al-MMK'ların mikroyapısal özellikleri hakkında değerlendirme yapmak amacıyla gerekli metalografik işlemler yapılarak mikroyapı incelemeleri gerçekleştirilmiştir. Yapılan SEM-EDS analizlerinde bor ve nikel elementleri tespit edilerek cam elyaflar üzerindeki kaplama varlığı doğrulanmıştır. Döküm sonrası döküm parçalarının tamamına T6 ısıl işlem yapılmıştır. Kalıpta katılaşan metal matriksli döküm parçasının T6 ısıl işlem sonrası işlenmiş olan numuneleri üzerinde X-ray ve bilgisayarlı tomografi görüntülemeleri yapılmıştır. Ni-B kaplı cam elyaf takviyeli A380 alaşımının dökümüne ait ısıl işlem görmüş numunenin XRD sonucu incelendiğinde, Ni3B fazına ait piklerin oluştuğu görülmüştür. Metal matriksin mekanik özellikleri analizi çekme ve darbe testleri yapılarak ölçülmüştür. Numunelerin nötral ortamdaki elektokimyasal korozyon testleri gerçekleştirilmiştir. Sonuç olarak cam elyaflara yapılan akımsız Ni-B kaplama işlemlerinin başarılı olduğu, metal matriks üretim yönteminde akımsız Ni-B kaplı cam elyafların alüminyum matriks içerisine dağıldığı, akımsız Ni-B kaplı cam elyafların topaklanmadığı belirlenmiştir. Yapılan darbe testleri sonucunda yapıyı akımsız Ni-B kaplı cam elyafların sünekleştirdiği tespit edilmiştir. Çekme testi sonuçlarına göre ise döküm yöntemindeki değişkenliklerin sonuçları bariz şekilde etkilediği belirlenmiştir. Yine yapılan elektrokimyasal deneylerde tüm koşullarda yakın sonuçlar gözlemlenmiştir.
Aluminum and its alloys have become an indispensable material, especially in the automotive and aviation industry. Al-MMC's which are strengthened with reinforcment elements lighter but stronger when compared with steel. Al-MMC's usage is increasing in the automotive and aviation industry. In this thesis, metal matrix composite (MMC) was produced by casting method using A380 (EN AC 46000) alloy as matrix and E class glass fiber as reinforcement element. The electroless coating process, which is one of the main subjects of this study, was used. The electroless coating of the coating material according to the ratio in order to gain industrial world boron reserves of high boron which are particularly selected in Turkey. Especially boron selected as a coating material in electroless coating due to the proportion of the world reserves having high boron in Turkey in order to gain it in industry. Firstly, electroless Ni-B coating process was applied to glass fibers. Then, the obtained coated glass fibers were added to the liquid aluminum using two different methods. In the first method, the coated glass fibers were mixed into the liquid aluminum with the help of a ladle on the crucible. In the other method, liquid alloy and Ni-B coated glass fibers were fed simultaneously into the gravity die without mixing. In order to evaluate the microstructural features of Al-MMCs and to evaluate Al-MMCs, microstructural studies were carried out after the necessary metallographic processes were performed. In the SEM-EDS analysis, boron and nickel elements were detected and the presence of coating on glass fibers was verified. After casting, T6 heat treatment was applied to all cast parts. X-ray and computed tomography images were performed on the samples for metal matrix cast part that was solidified in the mold after T6 heat treatment. When the XRD result of the heat treated sample belonging to the casting of Ni-B coated glass fiber reinforced A380 alloy was examined, it was observed that the peaks of the Ni3B phase were formed. Mechanical propertiy analysis of the metal matrix were measured by performing tensile and impact tests. Electrochemical corrosion tests of the samples in neutral environment were carried out. As a result, it was determined that electroless Ni-B coating processes applied to glass fibers were successful, electroless Ni-B coated glass fibers were dispersed in the aluminum matrix in metal matrix production method, and electroless Ni-B coated glass fibers were not agglomerated. As a result of the impact tests, it was determined that electroless Ni-B coated glass fibers ductile the structure. According to the tensile test results, it was determined that the variability in the casting method significantly affected the results. Similar results were observed in all conditions in electrochemical experiments.
Aluminum and its alloys have become an indispensable material, especially in the automotive and aviation industry. Al-MMC's which are strengthened with reinforcment elements lighter but stronger when compared with steel. Al-MMC's usage is increasing in the automotive and aviation industry. In this thesis, metal matrix composite (MMC) was produced by casting method using A380 (EN AC 46000) alloy as matrix and E class glass fiber as reinforcement element. The electroless coating process, which is one of the main subjects of this study, was used. The electroless coating of the coating material according to the ratio in order to gain industrial world boron reserves of high boron which are particularly selected in Turkey. Especially boron selected as a coating material in electroless coating due to the proportion of the world reserves having high boron in Turkey in order to gain it in industry. Firstly, electroless Ni-B coating process was applied to glass fibers. Then, the obtained coated glass fibers were added to the liquid aluminum using two different methods. In the first method, the coated glass fibers were mixed into the liquid aluminum with the help of a ladle on the crucible. In the other method, liquid alloy and Ni-B coated glass fibers were fed simultaneously into the gravity die without mixing. In order to evaluate the microstructural features of Al-MMCs and to evaluate Al-MMCs, microstructural studies were carried out after the necessary metallographic processes were performed. In the SEM-EDS analysis, boron and nickel elements were detected and the presence of coating on glass fibers was verified. After casting, T6 heat treatment was applied to all cast parts. X-ray and computed tomography images were performed on the samples for metal matrix cast part that was solidified in the mold after T6 heat treatment. When the XRD result of the heat treated sample belonging to the casting of Ni-B coated glass fiber reinforced A380 alloy was examined, it was observed that the peaks of the Ni3B phase were formed. Mechanical propertiy analysis of the metal matrix were measured by performing tensile and impact tests. Electrochemical corrosion tests of the samples in neutral environment were carried out. As a result, it was determined that electroless Ni-B coating processes applied to glass fibers were successful, electroless Ni-B coated glass fibers were dispersed in the aluminum matrix in metal matrix production method, and electroless Ni-B coated glass fibers were not agglomerated. As a result of the impact tests, it was determined that electroless Ni-B coated glass fibers ductile the structure. According to the tensile test results, it was determined that the variability in the casting method significantly affected the results. Similar results were observed in all conditions in electrochemical experiments.
Açıklama
Anahtar Kelimeler
Metalurji Mühendisliği, Metallurgical Engineering
