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The Inconel 718 superalloy is one of the most-used nickel based superalloys in the aerospace industry due to its superior mechanical properties, for instance, high thermal and chemical resistance, and high strength at elevated temperatures. However, the work hardening tendency, low thermal conductivity and high hardness of this superalloy cause early tool wear, leading to the material to be called as a hard-to-cut material. Therefore, deposition of a wear resistant hard coating on carbide cutting tools has a critical importance for longer tool life in milling operations of the Inconel 718 superalloy. In this study, carbide cutting tools were coated with multilayer nanocomposite TiAlSiN/TiSiN/TiAlN coating using the magnetron sputtering technique, and wear behavior of the coated tool was investigated during face milling of the Inconel 718 superalloy under dry conditions. Abrasive and adhesive wear mechanisms were founded as main failure mechanisms. The nanocomposite TiAlSiN/TiSiN/TiAlN coated carbide cutting tool gave better wear resistance, and thus it provided 1.7 times longer tool life and a smoother surface (Ra<0.18 μm) on the Inconel 718 material than the uncoated one.

Boron nitride based tribological coatings promise hope in tribological applications thanks to their excellent lubrication and heat resistance properties. However, the applicability of these coatings on cutting tools in machining applications is not well known and it needs to be revealed. Therefore, in this study, a boron nitride (BN) coating was deposited on carbide milling tools. Inconel 718 was used as workpiece material in face milling tests to determine the wear behavior of the BN coated carbide tools. Surface roughness and tool wear was recorded in relation with cutting length. Wear mechanisms on the coated carbide tools were determined using scanning electron microscopy in combination with energy dispersive spectroscopy. Abrasive and adhesive wear was found as main failure mechanisms on the worn tools. Approximately two times longer tool life was obtained with the BN coated carbide tools.

Korozyon, endüstride ve insan sağlığı açısından önem arz eden besin maddeleri muhafazası kadar ısıtma, soğutma ve iklimlendirme sistemlerinde de karşımıza çıkmaktadır. Akışkan hareketi olan, olmayan ve özellikle de yoğuşma ve buharlaşma olan borularda zamanla korozyon oluşmaktadır. Bazı metaller korozyona uğrama konusunda daha aktiftirler. İklimlendirme sistemlerinde boru malzemesi olarak korozyona uğrama konusunda daha az aktif olan bakır kullanılmaktadır. Bu çalışmada, korozyon konusunda daha aktif olan alüminyum ve daha az aktif olan bakır birlikte bir deney setinde ele alınarak oluşan korozyon ve bu malzemelerin nasıl etkilendiği incelenmiştir. İlk olarak bakır ve alüminyum metaller arasındaki potansiyel fark, (volt) cinsinden ölçülmüştür. Daha sonra tasarlanan sistemde anot-katot reaksiyonları oluşturularak sistemde korozyon artış miktarı ve ardından oluşan bu korozyonu azaltmak için farklı bir tasarım yapılmıştır. Yeni tasarlanan sistem deneysel olarak incelenmiş ve korozyondaki azalmanın miktarı gözlenmiştir.