本研究利用相變誘發延性(Transformation-induced plasticity, TRIP)之強化機制，藉由沃斯田鐵變形時相變化成麻田散鐵提高加工硬化率並延後頸縮的發生，如此使鋼材擁有高強度、高延性之特性。利用TRIP之重點須使沃斯田鐵能在室溫下穩定，本研究發展使用適當之軋延及熱處理製程來達到此目的。
為了使生產成本降低，符合工業界需求，所以選擇錳鋁含量較低之鋼材，本實驗研究鋼材不同退火時間和軋延程序所產生的微結構，及相關拉伸性質與變形組織。

In this study, the alloy content of Mn and Al of a transformation-induced plasiticity (TRIP) steel was reduced in order to reduce the production cost of this steel. By using the right combination of hot rolling, cold rolling and heat treatments, an ultrafine-grained TRIP steel was developed. The microstructure and tensile property of this steel have been studied. EBSD was used to measure the grain size of this alloy, and the phase fractions of ferrite and austenite during tensile test. It was found that strain-induced martensitic transformation occurred during tensile test, which increase the work hardening rate so that postponed the occurring of necking, and a high elongation was obtained together with a high tensile strength.

一、前言 1
二、文獻回顧 2
2-1 TRIP鋼 2
2-2沃斯田鐵穩定性 2
2-2-1沃斯田鐵晶粒尺寸 3
2-2-2 TRIP效應與沃斯田鐵位置與關係 4
2-2-3 TRIP鋼合金的影響 4
2-3 TRIP鋼與熱處理關係 5
2-3-1 不同階段熱處理對微結構之影響 5
2-3-2 退火溫度造成錳含量變化與機械性質關係 6
2-3-3熱處理對中錳鋼的微結構和機械性質影響 7
2-4機械性質 11
2-4-1 拉伸變形機制 12
2-4-2 不同微結構對機械性質關係 13
2-4-3 TRIP鋼的加工硬化行為 16
2-4-4 不同晶粒大小和形貌與TRIP效應間的關係 18
三、研究目的 20
四、實驗方法 21
4-1實驗材料 21
4-2 熱處理製程 21
4-3拉伸測試 21
4-4 微觀組織分析 22
4-5 X-ray繞射分析 23
五、實驗結果 24
5-1微結構觀察 24
5-1-1熱軋板微結構 24
5-1-2熱軋板退火後微結構 24
5-1-3冷軋板微結構 25
5-1-4冷軋板退火後微結構 25
5-2拉伸試驗 26
5-2-1機械性質 26
5-2-2拉伸後顯微組織觀察 27
5-2-3拉伸試片破斷面微結構觀察 29
5-3相分率分析 30
5-3-1 EBSD相分率分析結果 30
5-3-2 XRD相分率分析結果 30
5-4晶粒尺寸 31
5-5化學成份分析 31
六、討論 33
6-1 熱處理對微結構組織之影響 33
6-2 化學成份對微結構之影響 34
6-3沃斯田鐵分率 35
6-4 機械性質 35
6-5 拉伸後微結構變化 37
七、結論 38
八、參考文獻 39

[1] E.D. Moor, P.J. Gibbs, J.G. Speer, J.G. Schroth, D.K. Matlock., Strategies for third generation advanced high strength steel development, Iron and Steel Technology, 7 (2010) 133-144.
[2] P.J. Gibbs, E. De Moor, M.J. Merwin, B. Clausen, J.G. Speer, D.K. Matlock, Austenite Stability Effects on Tensile Behavior of Manganese-Enriched-Austenite Transformation-Induced Plasticity Steel, Metall. Mater. Trans. A-Phys. Metall. Mater. Sci., 42A (2011) 3691-3702.
[3] J.D. Yoo, K.-T. Park, Microband-induced plasticity in a high Mn–Al–C light steel, Materials Science and Engineering A, 496 (2008) 417-424.
[4] P.J. Jacques, Transformation-induced plasticity for high strength formable steels, Current Opinion in Solid State and Materials Science, 8 (2004) 259-265.
[5] B.C. De Cooman, Structure–properties relationship in TRIP steels containing carbide-free bainite, Current Opinion in Solid State and Materials Science, 8 (2004) 285-303.
[6] M.D. Meyer, D. .Vanderschueren, B.C.D. Cooman, The influence of the substitution of Si by Al on the properties of cold rolled CMnSi TRIP steels, The iron and steel institute of Japan International, 39 (1999) 813-822.
[7] T. Waterschoot, L. Kestens, B.C. De Cooman, Hot rolling texture development in CMnCrSi dual-phase steels, Metall. Mater. Trans. A-Phys. Metall. Mater. Sci., 33 (2002) 1091-1102.
[8] C. Mesplont, B.C. De Cooman, Effect of austenite deformation on crystallographic texture during transformations in microalloyed bainitic steel, Mater. Sci. Technol., 19 (2003) 875-886.
[9] G.I. Rees, K.D.H. Bhadeshia, BAINITE TRANSFORMATION KINETICS .2. NONUNIFORM DISTRIBUTION OF CARBON, Mater. Sci. Technol., 8 (1992) 994-996.
[10] T.N. Lomholt, Y. Adachi, A. Bastos, K. Pantleon, M.A.J. Somers, Partial transformation of austenite in Al-Mn-Si TRIP steel upon tensile straining: an in situ EBSD study, Mater. Sci. Technol., 29 (2013) 1383-1388.
[11] I.B. Timokhina, P.D. Hodgson, E.V. Pereloma, Effect of microstructure on the stability of retained austenite in transformation-induced-plasticity steels, Metallurgical and Materials Transactions A, 35 (2004) 2331-2341.
[12] S. Zaefferer, J. Ohlert, W. Bleck, A study of microstructure, transformation mechanisms and correlation between microstructure and mechanical properties of a low alloyed TRIP steel, Acta Materialia, 52 (2004) 2765-2778.
[13] E. Jimenez-Melero, N.H. van Dijk, L. Zhao, J. Sietsma, S.E. Offerman, J.P. Wright, S. van der Zwaag, Martensitic transformation of individual grains in low-alloyed TRIP steels, Scripta Materialia, 56 (2007) 421-424.
[14] S.C.X.L.W.Z.F.B.C.H.C.P.K. Liaw, Probing the characteristic deformation behaviors of transformation-induced plasticity steels, Metallurgical and Materials Transactions A, 39 (2008) 3105-3112.
[15] S.J. Kim, C.G. Lee, I. Choi, S. Lee, Effects of heat treatment and alloying elements on the microstructures and mechanical properties of 0.15 wt pct C transformation-induced plasticity-aided cold-rolled steel sheets, Metall. Mater. Trans. A-Phys. Metall. Mater. Sci., 32A (2001) 505-514.
[16] J. Maki, J. Mahieu, B.C. De Cooman, S. Claessens, Galvanisability of silicon free CMnAI TRIP steels, Mater. Sci. Technol., 19 (2003) 125-131.
[17] J. Mahieu, J. Maki, B.C. De Cooman, S. Claessens, Phase transformation and mechanical properties of Si-free CMnAl transformation-induced plasticity-aided steel, Metall. Mater. Trans. A-Phys. Metall. Mater. Sci., 33 (2002) 2573-2580.
[18] H.F. Xu, J. Zhao, W.Q. Cao, J. Shi, C.Y. Wang, C. Wang, J. Li, H. Dong, Heat treatment effects on the microstructure and mechanical properties of a medium manganese steel (0.2C–5Mn), Materials Science and Engineering: A, 532 (2012) 435-442.
[19] 呂俊仁, 國立中山大學材料與光電科學所, 碩士論文 (2013).
[20] A.F. Mark, X. Wang, E. Essadiqi, J.D. Embury, J.D. Boyd, Development and characterisation of model TRIP steel microstructures, Materials Science and Engineering A, A576 (2013) 108-117.
[21] K. Spencer, J.D. Embury, K.T. Conlon, M. Veron, Y. Brechet, Strengthening via the formation of strain-induced martensite in stainless steels, Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process., 387 (2004) 873-881.
[22] L. Bracke, L. Kestens, J. Penning, Transformation mechanism of alpha '-martensite in an austenitic Fe-Mn-C-N alloy, Scripta Materialia, 57 (2007) 385-388.
[23] X. Sun, K.S. Choi, A. Soulami, W.N. Liu, M.A. Khaleel, On key factors influencing ductile fractures of dual phase (DP) steels, Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process., 526 (2009) 140-149.
[24] E.Yang, H. Zurob, J. McDermid, Mechanical Behavior and Microstructural Evolution of Fe-22Mn-C TWIP/TRIP Steels as a Function of C Content, Mater. Sci. Technol., (2010) 1914-1925.
[25] G. Frommeyer, U. Brux, P.Neumann, Supra-Ductile and High-Strength Manganese-TRIP/TWIP Steels for High Energy Absorption Purposes, The iron and steel institute of Japan International, 43(3) (2003) 438-446.
[26] M.H. Cai, H. Ding, Z.Y. Tang, H.Y. Lee, Y.K. Lee, Strain Hardening Behavior of High Performance FBDP, TRIP and TWIP Steels, Steel Res. Int., 82(3) (2011) 242-248.
[27] M.C. McGrath, D.C. Van Aken, N.I. Medvedeva, J.E. Medvedeva, Work Hardening Behavior in Steel with Multiple TRIP Mechanisms, Metall. Mater. Trans. A-Phys. Metall. Mater. Sci., 44A (2013) 4634-4643.
[28] K.K. Park, S.T. Oh, S.M. Baeck, D.I. Kim, J.H. Han, H.N. Han, S.H. Park, C.G. Lee, S.J. Kim, K.H. Oh, In situ deformation behavior of retained austenite in TRIP steel, in: D.N. Lee (Ed.) Textures of Materials, Pts 1 and 2, Trans Tech Publications Ltd, Zurich-Uetikon, 2002, pp. 571-576.
[29] J. Kobayashi, D. Ina, Y. Nakajima, K.I. Sugimoto, Effects of Microalloying on the Impact Toughness of Ultrahigh-Strength TRIP-Aided Martensitic Steels, Metall. Mater. Trans. A-Phys. Metall. Mater. Sci., 44A (2013) 5006-5017.
[30] 歐志鴻, 國立中山大學材料與光電科學所, 碩士論文 (2013).
[31] 周紹誠, 國立中山大學材料與光電科學所, 碩士論文 (2014).