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3637 |
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Formation of intermetallic phases in Fe-Al binary cold spray thick deposit |
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Jan Cizek* / Institute of Materials Science and Engineering,
Brno University of Technology, Czech Republic Vit Jan / Institute of Materials Science and Engineering, Brno University of Technology, Czech Republic Lucie Palenikova/ Institute of Materials Science and Engineering, Brno University of Technology, Czech Republic Jan Cupera/ Institute of Materials Science and Engineering, Brno University of Technology, Czech Republic |
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Deposits of 60/40 at% Fe/Al were produced by low-pressure cold spray technique using heated air (300°C, 15 bar) as working gas. The chemical composition of the 8-10 mm thick deposits changed strongly favoring aluminum as compared to the original mixture composition. Samples of the deposited material were then annealed isothermally at temperatures from 250°C to 750°C for two hours in argon protective atmosphere. The overall change of material character during annealing was evaluated: changes in the character of fracture behavior, local micro hardness of the evolving phases and residual powder particles. Microstructure and chemistry of the newly formed phases was evaluated using analytical electron microscopy. Gradual evolution of intermetallic phases by diffusion mechanism at temperatures from 550°C was observed. The evolved phases included metastable and stable phases close to Al3Fe, FeAl, Al5Fe2 and Al2Fe. The samples general shape was preserved during the heating process due to a rapid formation of intermetallic skeleton (at temperatures exceeding aluminum melting temperature). The growth of external dimensions during the treatment and associated porosity evolution as well as the overall feasibility of the application of the presented technique for technically applicable materials is discussed. |