Abstract— Heat exchangers included in air conditioning systems for aircraft are produced by brazing stamped thin alloys sheets made of nickel-based alloys, Alloy 600 and Ni 201, or stainless steel, AISI 444. Separation metal sheets and locking bars of Alloy 625 are used to complete the system. The brazing filler metal, mainly composed of nickel, manganese, silicon and copper, is referred as BNi-8. In order to control brazing process, a good knowledge of both the brazing filler metal metallurgical behavior and of the interaction with the base metal is essential. The study of the brazing filler metal melting behavior in itself reveals that the melting point is highly dependent on the chemical composition and especially on silicon content. Microstructures analysis showed the presence of several phases with significant differences in terms of mechanical properties at a small scale which could induce local embrittlement. Interactions between the brazing filler metal and the different alloys constitutive of the assembly induce chemical composition evolutions related to the local configuration of the assembly. Dissolution and interdiffusion processes as well as chemical exchanges with the furnace environment occur. Finally, due to this set of phenomena, significant brazing defects can affect the mechanical integrity of the component.
Keywords— Brazing, Microstructure, Melting point, Nickel-based filler metal.
AD Publications is a rapidly growing academic publisher in the fields of Engineering, Medical-Health, Environmental Science and Agriculture Research. AD Publications is a registered organization broad-based open access and publishes most exciting researches with respect to the subjects of our journals. The Journals is being indexed and abstracted by all major global current awareness and alerting services.
The organization aims at undertaking, co- coordinating and promoting research and development. It provides professional and academic guidance in the field of basic education, Higher Education as well in the Technical Education. Our Aims is to Promote and support, High Quality basic, Scientific Research and development in fields of Engineering, Medical-Health, Environmental Science and Agriculture Research and to Generate Public awareness, provide advice to scholar’s researchers and communicate research outcomes.