Observation of high-temperature phase transformation in the Si-modified aluminide coating on mild steel using EBSD
- Department of Mechanical Engineering, National Taiwan University of Science and Technology, Taipei 10672, Taiwan (China)
Mild steel was coated by hot-dipping in a molten bath containing Al-10 wt.% Si. The phase transformation in the aluminide layer during diffusion at 750 deg. C in static air was analyzed by Electron Backscatter Diffraction. The results showed that the aluminide layer of the as-coated specimen consisted of an outer Al-Si eutectic topcoat and the inner Fe-Al-Si and Fe-Al intermetallic layers. The formation of {tau}{sub 5}-Al{sub 7}Fe{sub 2}Si and {tau}{sub 6}-Al{sub 4}FeSi was observed with increasing exposure time at 750 deg. C, while the {tau}{sub 1}-(Al,Si){sub 5}Fe{sub 3} phase precipitated into the Fe{sub 2}Al{sub 5} phase. After 60 min of exposure, the {tau}{sub 5}-Al{sub 7}Fe{sub 2}Si and {tau}{sub 6}-Al{sub 4}FeSi phases disappeared. The FeAl phase not only formed at the interface between Fe{sub 2}Al{sub 5} and the steel substrate, but also transformed from {tau}{sub 1}-(Al,Si){sub 5}Fe{sub 3} after diffusion for 10 h. With prolonged exposure, the growing FeAl phase decreased the thickness of Fe{sub 2}Al{sub 5} and forced the formation of FeAl{sub 2} phase. Finally, the aluminide layer comprised only FeAl{sub 2} and FeAl.
- OSTI ID:
- 22066205
- Journal Information:
- Materials Characterization, Vol. 61, Issue 4; Other Information: Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1044-5803
- Country of Publication:
- United States
- Language:
- English
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