Browsing by Author "Wang, C. S."

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Corrosion behaviors of austenitic Fe-30Mn-7Al-xCr-1C alloys in 3.5% NaCl solution
(2009-04-15)
Tuan, Y. H.
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Wang, C. S.
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Tsai, C. Y.
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Chao, C. G.
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Liu, T. F.
The corrosion behaviors of the as-quenched Fe-30wt.%Mn-7wt.%Al-xwt.%Cr-1 wt.%C alloys (x = 0, 3, 6 and 9) in 3.5% NaCl have been investigated. Passivation could be observed for all the alloys except for the alloy without Cr content. The corrosion potential (E(corr)) and pitting potential (E(pp)) increased pronouncedly with increasing Cr content up to 6 wt.%, and decreased as Cr content up to 9 wt.%. The decrease of E(corr) and E(pp) of the alloy containing 9 wt.% Cr was due to the formation of (Fe,Mn,Cr)(7)C(3) carbides in the austenite matrix and on the grain boundaries. It is noted that the corrosion behaviors of the austenitic Fe-Mn-Al-Cr-C alloys with higher Cr(>= 3 wt.%) content have never been reported in previous literatures. (C) 2008 Elsevier B.V. All rights reserved.
Phase transitions in an Fe-9Al-30Mn-2.0C alloy
(2007-11-01)
Wang, C. S.
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Hwang, C. N.
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Chao, C. G.
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Liu, T. F.
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The as-quenched microstructure of Fe-9Al-30Mn-2.0C alloy is austenite phase containing fine (Fe,Mn)(3)AlC carbides. When the alloy was aged at 900-1100 degrees C and then quenched, both large and extremely fine (Fe,Mn)(3)AlC carbides could be observed simultaneously within the austenite matrix. This feature has never before been observed in FeAlMnC alloy systems. In addition, the Al and Mn concentrations in the coarse (Fe,Mn)(3)AlC carbides formed on the grain boundaries were found to vary drastically with the aging temperature. (C) 2007 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
The effect of hot-dipped aluminum coatings on Fe-8Al-30Mn-0.8C alloy
(2008-02-01)
Su, C. W.
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Lee, J. W.
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Wang, C. S.
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Chao, C. G.
;
Liu, T. F.
The morphology and microstructure of an intermetallic layer formed on the surface of Fe-8Al-30Mn-0.8C alloy by hot-dip aluminization treatment have been examined in detail. The phases present in the coating are unambiguously identified by means of transmission electron microscopy. After alummization, a two layer coating was formed consisting of an external Al layer and a (Fe, Mn)(2)Al-5 intermetallic on top of the substrate. The (Fe,Mn)(2)Al-5 compound has an orthorhombic structure with lattice parameters a = 0.752 nm, b = 0.667 nm and c = 0.417 nm. The activation energy (E-FeMnAl) for the growth of such an intermetallic layer is calculated to be 52.7 kJ/mol. These results are different from those observed in aluminized low-carbon steel (E-Fe). The difference between E-FeMnAl and E-Fe is attributed to the alloying elements (Mn) in the present alloy. Environmental salt fog corrosion and high temperature oxidation tests were carried out to examine the corrosion and oxidation resistance. The results indicated that both the corrosion and oxidation resistance of the Fe-8Al-30Mn-0.8C alloy treated by hot-dip aluminization can be significantly increased. (C) 2007 Elsevier B.V. All rights reserved.