AlSi12(Fe) yüksek basınçlı döküm alaşımında SR ilavelerinin alaşımın mikroyapısı ve mekanik özellikleri üzerine etkisinin incelenmesi
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Dosyalar
Tarih
2021
Yazarlar
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Yayıncı
Bursa Teknik Üniversitesi, Lisansüstü Eğitim Enstitüsü
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Alüminyum ve alaşımları, özellikle otomotiv sektörünün ağırlık azaltma ve mukavemetten ödün vermeyecek şekilde hedeflerini karşılayacak kritik uygulamalarında kullanımı günden güne yaygınlaşan mühendislik malzemelerinden birisi haline gelmiştir. Bu tez çalışmasında; yüksek basınçlı döküm yöntemi kullanılarak üretilen AlSi12(Fe) alaşımına Sr modifikasyonu yapılarak, Sr miktarının alaşımın mekanik ve mikroyapısal karakteristiği üzerine etkisi incelenmiştir. Döküm denemeleri ile birlikte enjeksiyon presinde kullanılan parametreler ile aynı olacak şekilde, MagmaSoft ve Click2Cast yazılımları ile kalıp dolum ve katılaşma analizleri gerçekleştirilmiştir. Bu sayede sahada elde edilen veriler ile simülasyon programlarından elde edilen veriler doğrudan karşılaştırılabilmiştir. Çalışma kapsamında 0 ppm, 20 ppm, 40 ppm, 80 ppm ve 160 ppm olacak şekilde toplamda beş farklı Sr parametresi için beş ayrı döküm yapılmıştır. Döküm çalışmaları ile birlikte eş zamanlı olarak RPT numunelerinin elde edilmesi ve numunelerin karakterize edilmesiyle alaşımın artan Sr miktarına bağlı olarak metal kalitesi belirlenmiştir. Metal kalitesinin belirlenmesi için RPT numuneleri metalografik hazırlık işlemlerine tabi tutulmuştur. Hazırlanan numunelerin, bilgisayar ortamında yüzey analizleri gerçekleştirildikten sonra metal kalitesi belirlenmiştir. Yüzey analizi için kesim işlemi öncesinde RPT numuneleri, çentik darbe testi için numune hazırlık işlemi öncesinde lama çekme çubuğu ve çekme testi öncesi silindirik çekme çubuğu numuneleri için tahribatsız muayene yöntemlerinden biri olan X-Ray radyografi yöntemi kullanılarak numunelerin porozite incelemeleri gerçekleştirilmiştir. Mekanik karakterizasyon çalışmaları kapsamında; numunelerin sertlik ölçümleri, çentik darbe testleri ve silindirik çekme çubuğu için çekme testleri gerçekleştirilerek artan Sr miktarının, AlSi12(Fe) alaşımın mekanik özellikleri üzerine etkisi detaylı bir şekilde incelenmiştir. Artan Sr miktarına bağlı olarak silis morfolojisinde meydana gelecek değişiminin gözlemlenebilmesi için mikroyapısal analiz yapılmıştır. Artan Sr miktarına bağlı olarak mikroyapıda oluşan intermetalikler için SEM görüntülemesi gerçekleştirilerek ilgili fazlara noktasal, çizgisel ve alansal EDS analizleri gerçekleştirilmiştir. Sonuç olarak, yüksek basınçlı döküm yöntemi ile üretilen AlSi12(Fe) alaşımı özelinde artan Sr miktarına bağlı olarak alaşımın hem mikroyapısal hem de mekanik özelliklerinin olumlu yönde etkilendiği görülmüştür. Artan Sr miktarı ile birlikte AlSi12(Fe) alaşımının akma mukavemetinde, çekme mukavemetinde ve % uzama değerinde belirgin bir iyileşme tespit edilmiştir. Yapılan çentik darbe testinin sonuçlarına göre Sr miktarının artması ile alaşımın enerji sönümleme yeteneği iyileştirilmiştir. 160 ppm Sr kullanımı ile AlSi12(Fe) alaşımının süneklik özelliği belirgin bir şekilde geliştirildiği sonucuna varılmıştır.
Aluminium and its alloys have become one of the most widely used engineering materials due to meeting the weight reduction and higher strength targets of the automotive sector more particularly in critical applications. In this thesis; changes in microstructure and mechanical properties of AlSi12(Fe) high pressure die casting (HPDC) alloy based on Si modification via different amounts of Sr were investigated. Mould filling and solidification analyses of the AlSi12(Fe) HPDC alloy were carried out with the help of MagmaSoft and Click2Cast software. The simulation parameters and injection press parameters that were chosen used during casting were used the same to compare casted product versus simulation casting process results on the simulation programs. Since one of the main subjects of the study is to determine the effects of increased Sr amount on the mechanical properties of AlSi12(Fe) alloy. Therefore, five different castings were organized for five different Sr parameters as 0 ppm, 20 ppm, 40 ppm, 80 ppm, and 160 ppm respectively. The metal quality was determined depending on the increasing Sr content of the alloy by obtaining and characterizing the RPT samples simultaneously with the casting studies. In order to determine the metal quality, RPT samples were subjected to metallographic preparation processes. The metal quality was determined after the surface analyzes of RPT samples were carried out via SigmaScan. Porosity analyzes of the samples were carried out by using the X-Ray radiography method, which is one of the most well-known non-destructive testing methods, for the RPT samples before cutting for surface analysis, for the lama tensile bar before the sample preparation for the impact test, and for the cylindrical tensile bar samples before the tensile test. Within the scope of mechanical characterization studies; The hardness measurements of the samples, impact tests, and tensile tests for the cylindrical tensile bar were performed and the effect of the increased amount of Sr on the mechanical properties of the AlSi12(Fe) alloy was investigated in detail. In order to observe the change in Si morphology depending on the increasing amount of Sr, microstructure analyzes of the samples were carried out. SEM imaging was performed for the intermetallic formed in the microstructure due to the increasing amount of Sr, and point, linear, and areal EDS analyses were performed on the relevant phases. As a result, it was observed that both the microstructural and mechanical properties of the alloy were positively affected due to the increased amount of Sr in the AlSi12(Fe) alloy produced by the HPDC. A significant improvement in yield strength, tensile strength and % elongation value of AlSi12(Fe) alloy was determined with increasing Sr content. According to the results of the notch impact test, the energy absorption ability of the alloy was improved with the increase in the amount of Sr. It was concluded that the ductility of the AlSi12(Fe) alloy was significantly improved with the use of 160 ppm Sr.
Aluminium and its alloys have become one of the most widely used engineering materials due to meeting the weight reduction and higher strength targets of the automotive sector more particularly in critical applications. In this thesis; changes in microstructure and mechanical properties of AlSi12(Fe) high pressure die casting (HPDC) alloy based on Si modification via different amounts of Sr were investigated. Mould filling and solidification analyses of the AlSi12(Fe) HPDC alloy were carried out with the help of MagmaSoft and Click2Cast software. The simulation parameters and injection press parameters that were chosen used during casting were used the same to compare casted product versus simulation casting process results on the simulation programs. Since one of the main subjects of the study is to determine the effects of increased Sr amount on the mechanical properties of AlSi12(Fe) alloy. Therefore, five different castings were organized for five different Sr parameters as 0 ppm, 20 ppm, 40 ppm, 80 ppm, and 160 ppm respectively. The metal quality was determined depending on the increasing Sr content of the alloy by obtaining and characterizing the RPT samples simultaneously with the casting studies. In order to determine the metal quality, RPT samples were subjected to metallographic preparation processes. The metal quality was determined after the surface analyzes of RPT samples were carried out via SigmaScan. Porosity analyzes of the samples were carried out by using the X-Ray radiography method, which is one of the most well-known non-destructive testing methods, for the RPT samples before cutting for surface analysis, for the lama tensile bar before the sample preparation for the impact test, and for the cylindrical tensile bar samples before the tensile test. Within the scope of mechanical characterization studies; The hardness measurements of the samples, impact tests, and tensile tests for the cylindrical tensile bar were performed and the effect of the increased amount of Sr on the mechanical properties of the AlSi12(Fe) alloy was investigated in detail. In order to observe the change in Si morphology depending on the increasing amount of Sr, microstructure analyzes of the samples were carried out. SEM imaging was performed for the intermetallic formed in the microstructure due to the increasing amount of Sr, and point, linear, and areal EDS analyses were performed on the relevant phases. As a result, it was observed that both the microstructural and mechanical properties of the alloy were positively affected due to the increased amount of Sr in the AlSi12(Fe) alloy produced by the HPDC. A significant improvement in yield strength, tensile strength and % elongation value of AlSi12(Fe) alloy was determined with increasing Sr content. According to the results of the notch impact test, the energy absorption ability of the alloy was improved with the increase in the amount of Sr. It was concluded that the ductility of the AlSi12(Fe) alloy was significantly improved with the use of 160 ppm Sr.
Açıklama
Anahtar Kelimeler
Basınçlı döküm, Pressure die casting, Basınçlı döküm yöntemi, Pressure die casting method, Stronsiyum, Strontium, Metalurji Mühendisliği, Metallurgical Engineering, Mühendislik Bilimleri, Engineering Sciences
