15B30為硼系超高強度鋼，在麻田散鐵態時其強度達2000MPa，由於其高強度之特性，在結構鋼及汽車鋼板應用上有出色的表現。然而超高強度鋼之缺點為易受到氫脆效應的影響，在實際應用上此因素可能會造成無法預測之破壞。本實驗研究目標為建立氫脆破壞之評估方法及抗氫脆破壞之方法，藉由微合金元素鈮的添加與熱處理程序來達成。利用化學充氫及拉伸試驗發現15B30在麻田散鐵態下其抗氫脆能力最差，最大抗拉強度損失達70%，並且可以發現破斷面有明顯之沿晶破壞組織；將15B30經過回火200℃、300℃，及400℃處理後發現200℃有最佳抗氫脆能力，主要原因為ε碳化物在麻田散鐵板條內部析出，提供額外氫捕集位置。回火300℃及400℃時雪明碳鐵在板條間及先前沃斯田鐵晶界析出，此種界面之氫捕集位置使得氫脆破壞現象加劇，使得抗氫脆能力較回火200℃時差。添加鈮元素之改良型15B30Nb，內部會有(Nb,Ti)(CN)及NbC析出，對材料有晶粒細化之作用，此效應在回火狀態充氫拉伸發現有良好的抗氫脆能力。而從定應力拉伸試驗發現鈮添加後晶粒細化之15B30Nb經過較久的時間後才斷裂，顯示有較佳之抗氫脆能力。

15B30 steel, an ultra-high strength boron steel, has 2000MPa ultra-high tensile strength in martensitic state. Due to its high strength property, 15B30 steel is best used in structural steel and automotive plate. However, ultra-high strength steel is prone to hydrogen embrittlement in practical usage, which will lead to severe unpredictable fracture. The aims of this research are to build up an evaluation method of hydrogen embrittlement and find the effects niobium-additive and heat treatment on the hydrogen embrittlement of 15B30 steel. After chemical hydrogen charging, the as-quenched 15B30 exhibits the worst resistance of hydrogen embrittlement. Its percentage loss of UTS after hydrogen charging is about 70%, and the fractography is intergranular fracture. Through tempering processes in different temperatures, it is found that 200℃ tempering processing is effective to resist the hydrogen embrittlemet. This feature is mainly ascribed to the ε carbide precipitates in the martensite lath, which can provide additional hydrogen trapping site. The cementite will precipitate along martensite lath interface and prior austenite grain boundary during the tempering at 300℃ and 400℃. This type of hydrogen trapping sites lead to a weaker resistance to hydrogen embrittlement. Niobium-added 15B30, namely the 15B30Nb steel, can have the refined grains due to the existence of (Nb,Ti)(CN) and NbC precipitates. These refined grains could improve noticeably the hydrogen embrittlement resistance in the tempering state. Constant load test shows that the hydrogen pre-charged 15B30Nb steel could sustain a longer fracture time, which also reveals that the refined grains have better hydrogen embrittlement resistance.

誌謝 II
摘要 III
Abstract IV
目錄 VI
第一章 前言 1
第二章 文獻回顧 2
2-1 鋼鐵組織簡介 2
2-1-1 麻田散鐵 2
2-1-2 殘留沃斯田鐵 4
2-1-3 回火麻田散鐵 6
2-2 微合金元素添加對鋼材性質影響 11
2-2-1 硼元素添加對鋼材性質影響 11
2-2-2 鈦元素添加對鋼材性質影響 14
2-2-3 鈮元素添加對鋼材性質影響 15
2-2-4 鈮元素與鈦元素在鋼材中交互析出行為 20
2-3 氫誘發損傷 21
2-3-1 氫的來源 21
2-3-2 氫進入材料方式 21
2-3-3 氫在材料內部的捕集位置(Trapping site) 23
2-3-4 氫的滲透率(Permeability)、擴散率(Diffusivity)、溶解度(Solubility) 24
2-3-5 氫誘發損傷之種類 29
2-3-5-1 氫誘發腫泡(Hydrogen induced blistering) 29
2-3-5-2 內部氫氣析出造成破裂(Cracking from precipitation of internal hydrogen) 30
2-3-5-3 氫攻擊(Hydrogen attack) 31
2-3-5-4 氫化物析出造成破裂(Cracking from hydride formation) 32
2-3-5-5 氫脆(Hydrogen embrittlement) 32
2-4 氫脆理論 33
2-4-1 氫鍵結弱化理論(Hydrogen enhanced decohesion, HEDE) 33
2-4-2 吸收誘發差排發射理論(Adsorption Induced Dislocation Emission, AIDE) 34
2-4-3 氫致局部塑性變形 (Hydrogen Enhanced Localized Plasticity, HELP) 38
2-5 氫致延遲破壞 39
2-6 氫脆破斷形貌 41
2-7 影響氫脆效應之因素 43
2-7-1 氫濃度對氫脆效應的影響 43
2-7-2 應變速率對氫脆效應的影響 44
2-7-3 溫度對氫脆效應的影響 45
2-7-4 氫捕集位置對氫脆的影響 46
2-7-5 殘留沃斯田鐵與氫脆關係 47
2-7-6 先前沃斯田鐵晶界與氫脆關係 49
2-7-7 麻田散鐵及其回火組織與氫脆關係 50
2-7-8 超高強度合金鋼與氫脆關係 51
2-7-9 鋼鐵中元素與氫脆關係 52
第三章 實驗步驟 54
3-1 實驗流程 54
3-2 15B30及15B30Nb 54
3-3 熱處理 55
3-4 硬度試驗 56
3-5 拉伸試驗 56
3-6 化學充氫 57
3-7 氫含量分析 57
3-8 定應力拉伸試驗 57
3-9 顯微組織及破斷面觀察 59
第四章 結果與討論 61
4-1 成份分析 61
4-2 回火熱處理條件界定 61
4-3 顯微組織觀察 63
4-3-1 金相觀察 63
4-3-2 先前沃斯田鐵晶界觀察 64
4-3-3 TEM觀察 65
4-3-3-1 淬火態之殘留沃斯田鐵觀察 65
4-3-3-2 ε碳化物及雪明碳鐵觀察 66
4-3-3-3 15B30之氮化鈦觀察 74
4-3-3-4 15B30Nb之碳氮化鈮觀察 75
4-4 氫含量分析 82
4-5 拉伸試驗 82
4-5-1 空氣中拉伸 82
4-5-2 充氫拉伸 83
4-6 拉伸破斷面觀察 88
4-6-1 未充氫之拉伸破斷面觀察 88
4-6-2 充氫破斷面之觀察 89
4-7 定應力拉伸試驗 107
第五章 結論 111
第六章 參考文獻 112

1.Stormvinter, A., Low Temperature Austenite Decomposition in Carbon Steels, in Department of Materials Science and Engineering Division of Physical Metallurgy. 2012, KTH Royal Institute of Technology: Stockholm.
2.Stormvinter, A., et al., Effect of carbon content on variant pairing of martensite in Fe–C alloys. Acta Materialia, 2012. 60(20): p. 7265-7274.
3.Totten, G.E., Steel Heat Treatment: Metallurgy and Technologies. 2006: Taylor &; Francis.
4.Thomas, G., Retained austenite and tempered martensite embrittlement. Metallurgical Transactions A, 1978. 9(3): p. 439-450.
5.Wells, M.G.H., An electron transmission study of the tempering of martensite in an Fe-Ni-C alloy. Acta Metallurgica, 1964. 12(4): p. 389-399.
6.Speich, G., Tempering of low-carbon martensite. Trans Met Soc AIME, 1969. 245(12): p. 2553-2564.
7.Dippenaar, R. and R. Honeycombe, The crystallography and nucleation of pearlite. Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences, 1973. 333(1595): p. 455-467.
8.Sarikaya, M., A.K. Jhingan, and G. Thomas, Retained austenite and tempered martensite embrittlement in medium carbon steels. Metallurgical Transactions A, 1983. 14(6): p. 1121-1133.
9.Rickett, R. and J. Hodge. Notch-toughness of fully hardened and tempered low-alloy steels. in Proceedings-american society for testing and materials. 1951. Amer Soc Testing Materials 100 Barr Harbor Dr, W Conshohocken, Pa 19428-2959.
10.Birkle, A., et al., A metallographic investigation of the factors affecting the notch toughness of maraging steels. 1964, DTIC Document.
11.Quench hardening of steel. n. d.; Available from: http://www.keytometals.com/Articles/Art12.htm.
12.Mohrbacher, H. Metallurgical optimization of martensitic steel sheet for automotive applications. in Proceedings of international conference on advanced steels, Guilin, China. 2010.
13.Melloy, G.F., P.R. Summon, and P.P. Podgursky, Optimizing the boron effect. Metallurgical Transactions, 1973. 4(10): p. 2279-2289.
14.Tungtrongpairoj, J., V. Uthaisangsuk, and W. Bleck, Determination of Yield Behaviour of Boron Alloy Steel at High Temperature. Journal of Metals, Materials and Minerals, 2009. 19(1): p. 29-38.
15.Hannerz, N., Critical hot plasticity and transverse cracking in continuous slab casting with particular reference to composition. Transactions of the Iron and Steel Institute of Japan, 1985. 25(2): p. 149-158.
16.成田貴一, et al., 高&;#28809;&;#28809;床部&;#12395;&;#12362;&;#12369;&;#12427;&;#12481;&;#12479;&;#12531;化合物&;#12398;生成. 鐵&;#12392;鋼: 日本&;#37921;鋼協會&;#12293;誌, 1976. 62(5): p. 525-534.
17.Zou, H. and J.S. Kirkaldy, Carbonitride precipitate growth in titanium/niobium microalloyed steels. Metallurgical Transactions A, 1991. 22(7): p. 1511-1524.
18.Nagata, M., J. Speer, and D. Matlock, Titanium nitride precipitation behavior in thin-slab cast high-strength low-alloy steels. Metallurgical and Materials Transactions A, 2002. 33(10): p. 3099-3110.
19.DeArdo, A., J. Gray, and L. Meyer, Fundamental metallurgy of niobium in steel. Niobium, 1981: p. 685-759.
20.Deardo, A.J., Niobium in modern steels. International Materials Reviews, 2003. 48(6): p. 371-402.
21.MI Yong-feng1, C.J.-c., ZHANG Zheng-yan1,QI Hai-quan1,ZHOU Xiao-long1,YONG Qi-long2, Effect of Carbon Content on the Solubility of Niobium Carbide in Austenite. Iron and Steel, 2012. 47(3): p. 84-88.
22.Porter, D.A. and K.E. Easterling, Phase Transformations in Metals and Alloys, Third Edition (Revised Reprint). 1992: Taylor &; Francis.
23.Lupis, C.H.P., Chemical Thermodynamics of Materials. 1993: Prentice Hall.
24.Le Bon, A., J. Rofes-Vernis, and C. Rossard, Recrystallization and precipitation during hot working of a Nb-bearing HSLA steel. Metal Science, 1975. 9(1): p. 36-40.
25.Coladas, R., et al., Austenite grain growth in medium and high-carbon steels microalloyed with niobium. Metal science, 1977. 11(11): p. 509-516.
26.Weiss, I. and J. Jonas, Interaction between recrystallization and precipitation during the high temperature deformation of HSLA steels. Metallurgical Transactions A, 1979. 10(7): p. 831-840.
27.Wadsworth, J., J. Woodhead, and S. Keown, The influence of stoichiometry upon carbide precipitation. Metal science, 1976. 10(10): p. 342-348.
28.Gray, J.M. Niobium bearing steels in pipeline projects. in Niobium science and technology: Proc. Int. Symposium on Niobium, Orlando, Florida. 2001.
29.Ishizaki, K., et al., Manufacturing method of high tension, high toughness steel. 1974, US Patent 3,849,209.
30.Le Houillier, R., G. Begin, and A. Dube, A study of the peculiarities of austenite during the formation of bainite. Metallurgical Transactions, 1971. 2(9): p. 2645-2653.
31.Matsumoto, K., T. Okita, and C. Ouchi, Method of manufacturing high strength low alloys steel plates with superior low temperature toughness. 1980, Google Patents.
32.Silcock, J.M. and W. Tunstall, Partial dislocations associated with NbC precipitation in austenitic stainless steels. Philosophical Magazine, 1964. 10(105): p. 361-389.
33.Van Aswegen, J., R. Honeycombe, and D. Warrington, Precipitation on stacking faults in Cr-Ni austenitic steels. Acta metallurgica, 1964. 12(1): p. 1-13.
34.Kurdjumov, G. and A. Khachaturyan, Nature of axial ratio anomalies of the martensite lattice and mechanism of diffusionless γ→ α transformation. Acta Metallurgica, 1975. 23(9): p. 1077-1088.
35.Takechi, H., Metallurgical Aspects on Interstitial Free Sheet Steel From Industrial Viewpoints. ISIJ International, 1994. 34(1): p. 1-8.
36.Uemori, R. and M. Tanino, Study of ultra-fine precipitates in low alloy steels. Le Journal de Physique Colloques, 1987. 48(C6): p. C6-399-C6-404.
37.Hong, S.G., K.B. Kang, and C.G. Park, Strain-induced precipitation of NbC in Nb and Nb–Ti microalloyed HSLA steels. Scripta Materialia, 2002. 46(2): p. 163-168.
38.Iza-Mendia, A., et al., Precipitation of Nb in Ferrite After Austenite Conditioning. Part I: Microstructural Characterization. Metallurgical and Materials Transactions A, 2012. 43(12): p. 4553-4570.
39.Kolgatin, N.N., V.P. Teodorovich, and V.I. Deryabina, Effect of hydrogen on two-layer steel. Chemical and Petroleum Engineering, 1966. 2(5): p. 303-305.
40.Poulter, T.C. and L. Uffelman, The Penetration of Hydrogen Through Steel at Four Thousand Atmospheres. Journal of Applied Physics, 1932. 3(3): p. 147-148.
41.Weigel, J. and E. Fromm, Determination of hydrogen absorption and desorption processes in aluminum melts by continuous hydrogen activity measurements. Metallurgical Transactions B, 1990. 21(5): p. 855-860.
42.Louthan, M.R., Jr., Hydrogen Embrittlement of Metals: A Primer for the Failure Analyst. Journal of Failure Analysis and Prevention, 2008. 8(3): p. 289-307.
43.Bockris, J.O.M., et al., Comprehensive treatise of electrochemistry. Vol. 2. 1981: Springer.
44.Wroblowa, H., B.J. Piersma, and J.O.M. Bockris, Studies of the mechanism of the anodic oxidation of ethylene in acid and alkaline media. Journal of Electroanalytical Chemistry (1959), 1963. 6(5): p. 401-416.
45.Hirth, J.P., Effects of hydrogen on the properties of iron and steel. Metallurgical Transactions A, 1980. 11(6): p. 861-890.
46.Pundt, A. and R. Kirchheim, HYDROGEN IN METALS: Microstructural Aspects. Annual Review of Materials Research, 2006. 36(1): p. 555-608.
47.Pressouyre, G.M., A classification of hydrogen traps in steel. Metallurgical Transactions A, 1979. 10(10): p. 1571-1573.
48.Michler, T. and M.P. Balogh, Hydrogen environment embrittlement of an ODS RAF steel–Role of irreversible hydrogen trap sites. International Journal of Hydrogen Energy, 2010. 35(18): p. 9746-9754.
49.Szost, B.A., R.H. Vegter, and P.J. Rivera-Diaz-del-Castillo, Hydrogen-Trapping Mechanisms in Nanostructured Steels. Metallurgical and Materials Transactions A, 2013. 44(10): p. 4542-4550.
50.Pressouyre, G.M., Trap theory of Hydrogen embrittlement. Acta Metallurgica, 1980. 28(7): p. 895-911.
51.Xu, J., et al., Hydrogen permeation and diffusion in a 0.2 C–13Cr martensitic stainless steel. Scripta metallurgica et materialia, 1993. 29(7): p. 925-930.
52.Frappart, S., et al., Study of the hydrogen diffusion and segregation into Fe–C–Mo martensitic HSLA steel using electrochemical permeation test. Journal of Physics and Chemistry of Solids, 2010. 71(10): p. 1467-1479.
53.Devanathan, M. and Z. Stachurski, The adsorption and diffusion of electrolytic hydrogen in palladium. Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences, 1962. 270(1340): p. 90-102.
54.Tsay, L.W., et al., Effect of hydrogen environment on the notched tensile properties of T-250 maraging steel annealed by laser treatment. Corrosion Science, 2002. 44(6): p. 1311-1327.
55.Cheng, Y. and L. Niu, Mechanism for hydrogen evolution reaction on pipeline steel in near-neutral pH solution. Electrochemistry Communications, 2007. 9(4): p. 558-562.
56.Volkl, J. and G. Alefeld, Diffusion of hydrogen in metals, in Hydrogen in Metals I, G. Alefeld and J. Volkl, Editors. 1978, Springer Berlin Heidelberg. p. 321-348.
57.Bauccio, M. and A.S. Metals, ASM Metals Reference Book. 1993: ASM International.
58.Corrosion Consultancy. 2004, CorCon.
59.Gangloff, R.P., Hydrogen assisted cracking of high strength alloys. 2003, DTIC Document.
60.Gest, R. and A. Troiano, Stress corrosion and hydrogen embrittlement in an aluminum alloy. Corrosion, 1974. 30(8): p. 274-279.
61.Whiteman, M. and A. Troiano, Hydrogen embrittlement of austenitic stainless steel. Corrosion, 1965. 21(2): p. 53-56.
62.Oriani, R.A., The diffusion and trapping of hydrogen in steel. Acta Metallurgica, 1970. 18(1): p. 147-157.
63.Oriani, R., Hydrogen embrittlement of steels. Annual review of materials science, 1978. 8(1): p. 327-357.
64.Goken, M., H. Vehoff, and P. Neumann, Atomic force microscopy investigations of loaded crack tips in NiAl. Journal of Vacuum Science &; Technology B, 1996. 14(2): p. 1157-1161.
65.Lynch, S., Environmentally assisted cracking: overview of evidence for an adsorption-induced localised-slip process. Acta Metallurgica, 1988. 36(10): p. 2639-2661.
66.Beachem, C., A new model for hydrogen-assisted cracking (hydrogen “embrittlement”). Metallurgical Transactions, 1972. 3(2): p. 441-455.
67.Micromechanical and macroscopic modelling. n. d.; Available from: http://www.icams.de/content/departments/mmm/index.html?view=details&;project=47&;information=projects.
68.Troiano, A.R., The role of hydrogen and other interstitials in the mechanical behavior of metals. trans. ASM, 1960. 52(1): p. 54-80.
69.Pressouyre, G., Current solutions to hydrogen problems in steel. 1982.
70.Figueroa, D. and M. Robinson, The effects of sacrificial coatings on hydrogen embrittlement and re-embrittlement of ultra high strength steels. Corrosion Science, 2008. 50(4): p. 1066-1079.
71.McMahon Jr, C., Hydrogen-induced intergranular fracture of steels. Engineering Fracture Mechanics, 2001. 68(6): p. 773-788.
72.Bernstein, I. and A. Thompson, Hydrogen effects in metals. Warrendale, PA, Metallurgical Society of AIME, 1981, 1071 p, 1981.
73.Moody, N., M. Perra, and S. Robinson, Hydrogen pressure and crack tip stress effects on slow crack growth thresholds in an iron-based superalloy. Scripta Metallurgica, 1988. 22(8): p. 1261-1266.
74.Pao, P. and R. Wei, Hydrogen assisted crack growth in 18Ni (300) maraging steel. Scripta Metallurgica, 1977. 11(6): p. 515-520.
75.Toribio, J., The role of crack tip strain rate in hydrogen assisted cracking. Corrosion science, 1997. 39(9): p. 1687-1697.
76.Bromley, D.M., Hydrogen Embrittlement testing of austenitic stainless steels sus 316 and 316L. 2008.
77.Andreone, C. and A. Murut, Influence of the austenite retained in the hydrogen embrittlement in AISI 4340. Scripta Metallurgica et Materialia, 1990. 24(8): p. 1453-1458.
78.Enomoto, M., D. Hirakami, and T. Tarui, Thermal desorption analysis of hydrogen in high strength martensitic steels. Metallurgical and Materials Transactions A, 2012. 43(2): p. 572-581.
79.Maroef, I., et al., Hydrogen trapping in ferritic steel weld metal. International Materials Reviews, 2002. 47(4): p. 191-223.
80.Park, Y., et al., Retained austenite as a hydrogen trap in steel welds. Welding Journal-New York-, 2002. 81(2): p. 27-S.
81.Perez Escobar, D., et al., Combined thermal desorption spectroscopy, differential scanning calorimetry, scanning electron microscopy and X-ray diffraction study of hydrogen trapping in cold deformed TRIP steel. Acta Materialia, 2012. 60(6-7): p. 2593-2605.
82.Michler, T. and J. Naumann, Microstructural aspects upon hydrogen environment embrittlement of various bcc steels. International Journal of Hydrogen Energy, 2010. 35(2): p. 821-832.
83.Lessar, J. and W. Gerberich, Grain size effects in hydrogen-assisted cracking. Metallurgical Transactions A, 1976. 7(7): p. 953-960.
84.Bernstein, I. and A. Thompson, The Effects of Metallurgical Variables on the Environmental Fracture of Steels. 1975, DTIC Document.
85.Kameda, J., Equilibrium and growth characteristics of hydrogen-induced intergranular cracking in phosphorus-doped and high purity steels. Acta Metallurgica, 1986. 34(9): p. 1721-1735.
86.Takasawa, K., et al., Effects of grain size on hydrogen environment embrittlement of high strength low alloy steel in 45 MPa gaseous hydrogen. Strength, Fracture and Complexity, 2011. 7(1): p. 87-98.
87.Gehrmann, F., et al., Hydrogen Transport and Cracking in Metals. Institute of Materials, London, 1995: p. 216.