Microstructure and strength of γ-TiAl alloy/Inconel 718 brazed Joints
| Autor: | Anibal Lopes Guedes, Filomena Viana, E. W. Sequeiros, Manuel F. Vieira, A. M. P. Pinto |
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| Přispěvatelé: | Universidade do Minho |
| Jazyk: | angličtina |
| Rok vydání: | 2013 |
| Předmět: |
Materials science
Alloy Intermetallic Mechanical properties 02 engineering and technology engineering.material 01 natural sciences Indentation hardness gamma-TiAl based alloy 0103 physical sciences Brazing General Materials Science Inconel 010302 applied physics Ni superalloy Science & Technology Mechanical Engineering Metallurgy 021001 nanoscience & nanotechnology Condensed Matter Physics Microstructure γ-TiAl based alloy Superalloy ?-Tial based alloy Engenharia e Tecnologia::Engenharia dos Materiais Mechanics of Materials engineering 0210 nano-technology Electron backscatter diffraction |
| Popis: | Intermetallics and superalloys brazing development is a current topic owing the extending use of these alloys in industrial applications. In this work a γ-TiAl alloy was joined to Inconel 718 by active metal brazing, using Incusil-ABA as filler. Joining was performed at 730 °C, 830 °C and 930 °C, with a 10 min dwelling time. The interfaces were characterized by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS) and Electron Backscatter Diffraction (EBSD). For all processing conditions, the reaction between the base materials and the braze alloy produced multilayered interfaces. For all processing temperatures tested (Ag), (Cu), AlNi2Ti and AlCu2Ti were identified at the interface. Raising the brazing temperature increased the thickness of the interface and coarsened its microstructure. The increase of the extension of the interface was essentially due to the growth of the reaction layers formed near each base material, which were found to be mainly composed of intermetallic compounds. The mechanical behavior of the joints, at room temperature, was assessed by microhardness and shear tests. For all processing conditions the hardness decreases from periphery towards the Ag-rich centre of the joints. Brazing at 730 °C for 10 min produced the joints with the highest average shear strength (228±83 MPa). SEM and EDS analysis of the fracture surfaces revealed that fracture of joints always occurred across the interface, preferentially through the hard layer, essentially composed of AlNi2Ti, resulting from the reaction between Inconel 718 and the braze alloy. This work was supported by "FCT-Fundacdo para a Ciencia e Tecnologia" through the project PTDC-CTM-69646-2006. |
| Databáze: | OpenAIRE |
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