Browsing by Author "Liu, T. F."

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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.
Effect of compressive stress on nickel-induced lateral crystallization of amorphous silicon thin films
(2012-01-31)
Huang, S. Y.
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Lin, H. L.
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Chao, C. G.
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Liu, T. F.
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材料科學與工程學系
The present study describes a method enabling the metal-induced lateral crystallization (MILC) of amorphous silicon (a-Si) films. Glass substrates coated with a-Si films were contacted with ground nickel sheets under compressive stresses ranging from 3.7 to 265.8 MPa at 550 degrees C for 1 h. Subsequently, the nickel sheet and stress were removed and the specimens were annealed at 550 degrees C for 1 to 4 h. The experimental results indicate that the extent of MILC decreased when the preliminary compressive stress was increased, while all specimens exhibited the same rate of lateral crystallization during annealing. The present study indicates that, by applying an appropriate compressive stress (similar to 4 MPa), an effective method to reduce the residual Ni content in polycrystalline silicon (poly-Si) can be obtained. (C) 2011 Published by Elsevier B.V.
Excellent combination of strength and ductility in an Fe-9Al-28Mn-1.8C alloy
(2010-07-01)
Chang, K. M.
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Chao, C. G.
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Liu, T. F.
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材料科學與工程學系
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Department of Materials Science and Engineering
An optimal aging at 450 degrees C resulting in the subject alloy possessing a high yield strength of 1383 MPa with 32.5% elongation. With almost equivalent elongation, the yield strength was about 28% higher than that of FeAlMnC (C <= 1.3 wt.%) alloys after solution heat-treatment or controlled-rolling followed by optimal aging. Additionally, due to pre-existing fine (Fe,Mn)(3)AlC carbides in as-quenched alloy, the aging time required for attaining the optimal combination of strength and ductility was much less than that for FeAlMnC (C <= 1.3 wt.%) alloys. (C) 2010 Acta Materialia Inc. Published by Elsevier Ltd. 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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交大名義發表
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.