錳鋁合金鋼是學術界研發中的低密度不銹鋼，具有取代部份傳統鎳鉻系不銹鋼的潛力；而相變化的研究則是提供發展錳鋁系不銹鋼的必要基礎。本論文即研究鐵-14.2錳-3.93鋁-0.16碳(wt.%)合金鋼經不同熱處理後的相變化情形；熱處理包括：1300℃、1200℃和1100℃的高溫熱處理與經1100℃的固溶處理後於900℃以下的低溫作恆溫處理。本合金鋼的金相組織如下：於1300℃和1200℃時是由肥粒體及沃斯田體所共同組成；於1100℃是為單一沃斯田體相；而於900℃以下低溫時亦為由肥粒體及沃斯田體所組成的雙相組織。當於900℃以下溫度作恆溫處理後，合金鋼的肥粒體多數是以BCC麻田散體形式出現，其是於高溫水淬過程中生成，而於後續的恆溫處理時維持其原形貌；且合金鋼內皆有BCC肥粒體晶粒的析出。於穿透式電子顯微鏡試片薄區處可觀察到由肥粒體{110}平面組成的規則形狀的十二面體類負晶型孔洞，此種十二面體類負晶型孔洞是首次被觀察到。

Fe-C-Mn-Al steels have the potential to substitute for commercial Ni-Cr stainless steels. For the development of Fe-C-Mn-Al stainless steels, phase transformations play an important role. Our methods of studying the phase transformations of the Fe-0.16C-14.2Mn-3.93Al steel include heating, cooling, and/or annealing. The results of our study show that martensitic transformation, ordering reaction and the precipitation of ferrite occur in the Fe-C-Mn-Al steel. After cooling, most of the austenite transforms into ferritic martensite. In addition, the ferrite phase nucleates and grows in the prior austenite matrix after quenching and annealing. Besides, from the TEM observation, we have discovered negative dodecahedron crystals which have not been observed previously. The negative dodecahedron crystals surrounded by 12 {110} ferritic planes are from the electo-polishing of the TEM sample preparation. When holes form in the thin areas of the TEM specimen during electro-polishing, the inner high index surfaces with high surface energies have been removed and the {110} planes with the lowest surface energy have been reserved. Thus, the negative dodecahedron crystals form.

1. S.K. Chen, K.W. Chour, W.B. Lee, C.M. Wan, J.G. Byrne, Mat. Res. Bull., 25, 1115 (1990).
2. M.C. Li, H. Chang, P.W. Kao, D. Gan, Mater. Chem. Phys., 59, 96 (1999).
3. 龔吉合、潘德華、楊希文、傅承祖、施並裕、丁原傑，材料科學導論(機械材料)，滄海書局，310 (1998)。
4. 吳孟哲，“鐵錳鋁合金內體心立方麻田散體的研究”，國立台灣科技大學，碩士論文 (2013)。
5. D.A. Porter and K.E. Easterling, Phase Transformations in Metals and Alloys, 3/e, Nelson Thornes, (2008).
6. 劉禎祥、蔡全華，鑄鋼實務，中華民國鑄造協會，169 (1991)。
7. R.E. Reed-Hill, Physical Metallurgy Principle, 3/e, PWS, (1992).
8. G.E. Dieter, Mechanical Metallurgy, SI Metric (ed.), 132 (1988).
9. Z. Nishiyama, Martensitic Transformation, Academic Press (1978).
10. 崔占全、王昆林、吳潤，金屬學與熱處理，北京大學出版社，236 (2010)。
11. L. Cheng, X.L. Wan, K.M. Wu, Mater. Char., 61, 192 (2010).
12. 林郁珊，以方位影像顯微學分析鐵錳鋁合金內沃斯田體晶粒的麻田散體相變化，國立台灣科技大學，碩士論文 (2014)。
13. W.C. Cheng, C.F. Liu, Y.F. Lai, Mater. Sci. Eng. A, 337, 281 (2002).
14. D.J. Schmatz, Trans. AIME, 215, 112 (1959).
15. K.H. Hwang, C.M. Wan, J.G. Byrne, Scripta Metall, 24, 979 (1990).
16. W.C. Cheng, C.F. Liu, and Y.F. Lai, Scripta Metall., 48, 295 (2003).
17. D.B. Williams, C.B. Carter, Transmission Electron Microscopy, Kluwer/Plenum, New York (1996).
18. 陳力俊等，材料電子顯微鏡學，國科會精儀中心¬ (1997)。
19. C. Viti, M.L. Frezzotti, Linthos, 55, 125 (2001).