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5973 |
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Tuesday, May 21, 2019, Saal Brüssel 3:40 PM Brazing for turbine applications |
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Influence of superalloy additives on the melting behavior of green tapes for gas turbine repair brazing |
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Stefanie Wiesner / Surface Engineering Institute, RWTH Aachen University, Germany Minhaz Uddin* / Innobraze GmbH, Germany Harald Krappitz/ Innobraze GmbH, Germany Mehmet Öte/ Surface Engineering Institute, RWTH Aachen University, Germany Kirsten Bobzin/ RWTH Aachen University, Germany Stefanie Wiesner/ RWTH Aachen University, Germany |
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Gas turbine blades and vanes are subjected to a variety of high temperature, high stress corrosion and oxidation conditions which cause various types of degradations. Material is removed from the surface of such turbine components due to thermal, chemical and mechanical stresses during operation. The original geometry and mechanical properties of the components can be restored by repair brazing. Flexible polymer bonded green tapes consisting of brazing filler metal and Ni/Co-based superalloy powders can be used for this purpose. The focus of this study is on the behavior of green tapes made of a standard Ni-based brazing filler metal or an activated diffusion braze alloy and different Ni-based superalloys. Influence of the grain size of brazing alloy and superalloy additives and their proportion on green tapes is analyzed. Porosity as well as shrinkage of the green tapes after brazing is optimized. The melting behavior of the green tapes as well as the microstructure development due to the metallurgical interactions between brazing filler metals and Mar M 247 and René 80 superalloy additives are analyzed and compared. |