Browsing by Author "LIU, TF"

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2H PHASE IN A CU2MNAL ALLOY
(1994-09-15)
JENG, SC
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LIU, TF
;
交大名義發表
;
材料科學與工程學系
;
National Chiao Tung University
A NEW PHASE IN AN FE-9.0AL-29.5MN-1.2SI ALLOY
(1991-06-01)
WU, CC
;
LIU, TF
;
機械工程學系
;
材料科學與工程學系
;
Department of Mechanical Engineering
A new type of precipitate (designated L phase) was observed within the ferrite matrix in an Fe-9.0Al-29.5Mn-1.2Si alloy after being aged at 550-degrees-C. Transmission electron microscopy examinations indicated that the L-phase precipitate has a monoclinic structure with lattice parameters a = 0.656 nm, b = 0.797 nm, c = 0.637 nm, and beta = 109.4 deg, and the orientation relationship between the L-phase precipitate and the ferrite matrix could be stated as follows: (1BAR01)alpha-parallel-to (001)L-phase (1BAR10)alpha-parallel-to (1BAR11)L-phase with a deviation of 0.3 deg (011)alpha-parallel-to (131)L-phase with a deviation of 1.5 deg The L phase has never been observed in various Fe-Al-Mn, Fe-Mn-Si, Fe-Al-Si, and Mn-Al-Si alloy systems before.
AS-QUENCHED MICROSTRUCTURE OF A CU-32MN-25AL ALLOY
(1992-05-15)
LIU, TF
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JENG, SC
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交大名義發表
;
材料科學與工程學系
;
National Chiao Tung University
BETA-MN STRUCTURE IN AN FE-AL-MN-CR ALLOY
(1989-07-01)
LIU, TF
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WU, CC
;
交大名義發表
;
機械工程學系
;
National Chiao Tung University
EFFECT OF SI ADDITION ON THE MICROSTRUCTURE OF AN FE-8.0AL-29.0MN-0.90C ALLOY
(1990-07-01)
LIU, TF
;
CHOU, JS
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WU, CC
;
機械工程學系
;
材料科學與工程學系
GRAIN-BOUNDARY PRECIPITATION IN AN FE-28.6MN-9.8AL-0.8SI-1.0C ALLOY
(1991-07-01)
CHAO, CY
;
LIU, TF
;
交大名義發表
;
材料科學與工程學系
;
National Chiao Tung University
GRAIN-BOUNDARY PRECIPITATION IN AN FE-7.8AL-31.7MN-0.54C ALLOY
(1993-01-01)
CHAO, CY
;
HWANG, CN
;
LIU, TF
;
交大名義發表
;
材料科學與工程學系
GRAIN-BOUNDARY PRECIPITATION IN AN FE-8.0AL-31.5MN-1.05C ALLOY
(1993-01-15)
HWANG, CN
;
CHAO, CY
;
LIU, TF
;
交大名義發表
;
材料科學與工程學系
L-J PHASE IN A CU2.2MN0.8AL ALLOY
(1995-06-01)
JENG, SC
;
LIU, TF
;
機械工程學系
;
材料科學與工程學系
;
Department of Mechanical Engineering
A new type of precipitate (designated L-J phase) with two variants was observed within the (DO3 + L2(I)) matrix in a Cu2.2Mn0.8Al alloy. Transmission electron microscopy examinations indicated that the L-J phase has an orthorhombic structure with lattice parameters a = 0.413 nm, b = 0.254 nm and c = 0.728 nm. The orientation relationship between the L-J phase and the matrix is (100)(L-J)//($($) over bar$$ 011)(m), (010)(L-J)//(1 ($) over bar 1 ($) over bar 1)(m) and (001)(L-J)//(211)(m). The rotation axis and rotation angle between two variants of the L-J phase are [021] and 90 deg. The L-J phase has never been observed in various Cu-Al, Cu-Mn, and Cu-Al-Mn alloy systems before.
MORPHOLOGY OF A12-ALPHA-MN STRUCTURE
(1987-09-01)
LIU, TF
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TASY, JC
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交大名義發表
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機械工程學系
;
National Chiao Tung University
ORIENTATION RELATIONSHIPS AMONG M23C6, M6C, AND AUSTENITE IN AN FE-MN-AL-MO-C ALLOY
(1990-03-01)
LIU, TF
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PENG, SW
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LIN, YL
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WU, CC
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機械工程學系
PHASE-TRANSFORMATION IN AN FE-10.1AL-28.6MN-O.46C ALLOY
(1991-10-01)
WU, CC
;
CHOU, JS
;
LIU, TF
;
機械工程學系
;
材料科學與工程學系
The microstructure of an (alpha + gamma) duplex Fe-10.1A1-28.6Mn-0.46C alloy has been investigated by means of optical microscopy and transmission electron microscopy (TEM). In the as-quenched condition, extremely fine D0(3) particles could be observed within the ferrite phase. During the early stage of isothermal aging at 550-degrees-C, the D0(3) particles grew rapidly, especially the D0(3) particles in the vicinity of the alpha/gamma grain boundary. After prolonged aging at 550-degrees-C, coarse K-phase (Fe, Mn)3AlC precipitates began to appear at the regions contiguous to the D0(3) particles, and beta-Mn precipitates occurred on the alpha/gamma and alpha/alpha grain boundaries. Subsequently, the grain boundary beta-Mn precipitates grew into the adjacent austenite grains accompanied by a gamma --> alpha + beta-Mn transition. When the alloy was aged at 650-degrees-C for short times, coarse K-phase precipitates were formed on the alpha/gamma grain boundary. With increasing the aging time, the alpha/gamma grain boundary migrated into the adjacent austenite grain, owing to the heterogeneous precipitation of the Mn-enriched K phase on the grain boundary. However, the alpha/gamma grain boundary migrated into the adjacent ferrite grain, even though coarse K-phase precipitates were also formed on the alpha/gamma grain boundary in the specimen aged at 750-degrees-C.
PHASE-TRANSFORMATION IN AN FE-9.0AL-29.5MN-1.2SI ALLOY
(1991-06-01)
LIU, TF
;
UEN, GC
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CHAO, CY
;
LIN, YL
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WU, CC
The microstructure of an (alpha + gamma) duplex Fe-9.0Al-29.5Mn-1.2Si alloy has been investigated by means of transmission electron microscopy. In the as-quenched condition, extremely fine D0(3) particles were formed within the ferrite matrix by a continuous ordering transition during quenching. After being aged at 550-degrees-C, the extremely fine D0(3) particles existing in the as-quenched specimen grew preferentially along [100] directions. With increasing the aging time at 550-degrees-C, a (Si, Mn)-rich phase (designated as "L phase") began to appear at the regions contiguous to the D0(3) particles. The L phase has never been observed in various Fe-Al-Mn, Fe-Al-Si, Fe-Mn-Si, and Mn-Al-Si alloy systems before. When the as-quenched specimen was aged at temperatures ranging from 550-degrees-C to 950-degrees-C, the phase transformation sequence occurring within the (alpha + D0(3)) region as the aging temperature increases was found to be (alpha + D0(3) + L phase) --> (alpha + D0(3) + A13 beta-Mn) --> (B2 + D0(3) + A13 beta-Mn) --> (B2 + A13 beta-Mn) --> (alpha + A13 beta-Mn) --> (alpha + gamma) --> alpha.
PHASE-TRANSFORMATIONS IN AN FE-7.8AL-29.5MN-1.5SI-1.05C ALLOY
(1993-09-01)
CHAO, CY
;
LIU, TF
;
機械工程學系
;
材料科學與工程學系
;
Department of Mechanical Engineering
Phase transformations in an Fe-7.8Al-29.5Mn-1.5Si-1.05C alloy have been investigated by means of optical microscopy and transmission electron microscopy. In the as-quenched condition, a high density of fine (Fe,Mn)3AlC carbides could be observed within the austenite matrix. When the as-quenched alloy was aged at temperatures ranging from 550-degrees-C to 825-degrees-C, a gamma --> coarse (Fe,Mn)3AlC carbide + DO3 reaction occurred by a cellular precipitation on the gamma/gamma grain boundaries and twin boundaries. Both of the observations are quite different from those observed by other workers in Fe-Al-Mn-C alloys. In their studies, it was found that the as-quenched microstructure was austenite phase (gamma), and (Fe,Mn)3AlC carbides could only be observed within the austenite matrix in the aged alloys. In addition, a gamma --> alpha (ferrite) + coarse (Fe,Mn)3AlC carbide reaction or a gamma --> alpha + coarse (Fe,Mn)3AlC carbide + beta-Mn reaction was found to occur on the gamma/gamma grain boundary in the aged Fe-Al-Mn-C alloys.
PHASE-TRANSITION IN AN FE-23.2AL-4.1NI ALLOY
(1992-05-01)
LIU, TF
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JENG, SC
;
WU, CC
;
機械工程學系
;
材料科學與工程學系
The phase transition in an Fe-23.2 at. pct Al-4.1 at. pct Ni alloy has been investigated by means of transmission electron microscopy. In the as-quenched condition, the microstructure of the alloy is a mixture of (A2 + B2) phases. When the as-quenched alloy is aged at temperatures ranging from 500-degrees-C to 1050-degrees-C, the phase transition sequence is found to be (A2 + B2*) --> (B2 + B2*) --> B2 --> A2, where B2* is also a B2-type phase. It is worthwhile to note that the coexistence of two kinds of ordered B2 phase has not previously been observed by other workers in the Fe-Al-Ni ternary alloy system.
SPINODAL DECOMPOSITION IN FE-9.0AL-30.5MN-XC ALLOYS
(1993-09-01)
CHAO, CY
;
HWANG, LK
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LIU, TF
;
交大名義發表
;
材料科學與工程學系
THE ORIENTATION RELATIONSHIP BETWEEN A13 BETA-MN AND FERRITE
(1989-08-01)
LIU, TF
;
WU, CC
;
交大名義發表
;
機械工程學系
;
National Chiao Tung University