Browsing by Author "Tuan, YiHsuan"

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Effect of Carbon on Spinodal Decomposition in Fe-26Mn-20Al-C Alloys
(2011-03-01)
Tsay, GowDong
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Tuan, YiHsuan
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Lin, ChihLung
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Chao, ChuenGuang
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Liu, TzengFeng
The supersaturated austenite (gamma) phase decomposed into fine C-rich ordered k' particles and C-depleted gamma(0) phase during quenching in alloys with 5.5 <= C <= 8.0 at%. The misfit between k' particles and gamma(0) phase decreased with increasing carbon content. The strain energy increased dramatically as carbon content approached slightly below 5.5 at%. Undercooling may be insufficient to overcome the strain energy effects, thus leading to the absence of spinodal decomposition and k' particles in the present and prior austemtic FeMnAlC alloys with 3.1 <= C <= 5.2 at% under the as-quenched condition. Additionally, both the amount of ordered k' particles and the carbon concentration in the k' particles increased with increasing carbon content of the alloy. These results revealed that a higher degree of carbon supersaturation in the initial gamma phase might promote a tendency toward C-rich k' particle formation during quenching. [doi:10.2320/matertrans.M2010255]
Formation of Hagg Carbide in an Fe-30Mn-10Al-4Cr-0.45C Alloy
(2010-06-01)
Tuan, YiHsuan
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Chao, ChuenGuang
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Liu, TzengFeng
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材料科學與工程學系
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Department of Materials Science and Engineering
When the present alloy was aged at 550 degrees C, Hagg carbides (M(5)C(2)-type carbides) formed at a/2 < 100 > anti-phase boundaries of the D0(3) domains The Hagg carbide has never been observed by previous workers in FeMnAlC and FeMnAlCrC alloy systems The orientation relationship between Hagg carbide and D0(3) matrix was determined to be ((5) over bar 10)(M5C2) // (1 (1) over bar0)(D03) and (13 (4) over bar)(M5C2) // (10 (2) over bar )D0(3) The orientation relationship between Hagg carbide and bcc-type phase has also never been reported before [doi 10.2320/matertrans.M2010055]
Phase Separation from L2(1) to (B2+L2(1)) in Fe-24.6Al-7.5Ti Alloy
(2010-10-01)
Tsay, GowDong
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Su, ChunWei
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Tuan, YiHsuan
;
Chao, ChuenGuang
;
Liu, TzengFeng
As quenched microstructure of the Fe 24 6 at% Al 7 5 at% Ti alloy was a mixture of (A2+L2(1)) phases When the as quenched alloy was aged at 1173 K for moderate times the L2(1) domains grew considerably and B2 phase was formed at a/2(100) anti phase boundaries (APBs) as well as phase separation from well grown L2(1) to (B2+L2(1)*) occurred basically contiguous to the APBs where L2(1)* is also a L2(1) type phase With continued aging at 1173K the phase separation would proceed toward the whole well grown L2(1) domains This microstructural evolution has not been reported in the Fe Al Ti alloy systems before [doi 10 2320/matertrans M2010167]