臺灣博碩士論文加值系統

本研究藉由示差掃瞄熱卡計 (DSC)、光學顯微鏡(OM)、掃瞄式電子顯微鏡 (SEM/EDS)、X光繞射儀(XRD)、高溫拉伸試驗機及電化學極化曲線分析儀，來探討鎂-9wt. %鋰(L9)和鎂-9 wt. %鋰-1wt. %鋅(LZ91)合金之高低溫拉伸性質與腐蝕性質。研究結果顯示L9和LZ91鎂合金室溫之拉伸強度範圍僅約在120-140MPa，遠低於一般結構用金屬之強度。氧化試驗顯示鎂-鋰合金會有兩種氧化物生成: 一種為顆粒較細且富黏著性之MgO，另一種為顆粒較大之Li2O2且其含量在LZ91鎂合金比L9鎂合金多。不論在自來水或3.5% NaCl溶液中，LZ91鎂合金所量測到之電流密度皆低於L9鎂合金。在鎂-9 wt. %鋰合金中所添加之1wt. %鋅來增加其抗蝕性，主要歸功於其合金化效應來減少Gibbs自由能，進而降低合金中之反應速率(i.e.腐蝕電流密度)。

In this study room temperature and elevated temperature tensile properties and corrosion properties in Mg-9 wt. % Li (L9) and Mg-9 wt. % Li-1 wt. % Zn (LZ91) alloys are investigated by using DSC, OM, SEM/EDS, XRD, elevated temperature tensile tester and potentio-dynamic polarization. The results showed that the room temperature tensile strengths of L9 and LZ91 alloys are in the range of 120-140 MPa, which can hardly be qualified for structural applications. Oxidation test showed that there are two types of oxides formed on the Mg-Li alloys: fine cohesive granular oxide of MgO and coarse particle-like oxide of Li2O2, and that the amount of coarse particle-like Li2O2 was found to be greater in the LZ91 alloy than in the L9 alloy. The corrosion current densities of LZ91 alloy tested in both the tap water and the 3.5% NaCl solution are lower than those of L9 alloy tested under the same electrolytes. The improvement of corrosion resistance in Mg-9%Li alloy by addition of 1% Zn is attributed mainly to an alloying effect to decrease the Gibbs free energy of the alloy and to, consequently, reduce the reaction rate (i.e. the corrosion current density) in the alloy.

CONTENT
CHINESE ABSTRACT
ENGLISH ABSTRACT
CONTENT
LIST OF TABLES
LIST OF FIGURES

CHAPTER Ⅰ
INTRODUCTION...1
CHAPTER Ⅱ
LITERATURE REVIEW... 2
2.1 Magnesium-lithium alloys...3
2.1.1 Development of ultra light Magnesium-lithium alloys...3
2.1.2 Basis for ternary and complex alloys...4
2.2 Deformation of Mg-Li-base alloys by rolling...8
2.3 The effect of strain energy on high temperature mechanical properties...9
2.3.1 The relationship of free energy to strain energy...10
2.3.2 The release of stored energy...11
2.4 Dynamic recovery and dynamic recrystallization...13
2.4.1 Dynamic recovery...13
2.4.2 Dynamic recrystallization...14
2.4.3 Discontinuous and continuous recrystallization...17
2.5 Recent progress in improving the formability/ductility in Mg alloys...18
2.5.1 Development of Mg-base alloys with lithium...19
2.5.2 Cold and hot working of Mg alloys...19
2.5.3 Superplasticity in Mg alloys...20
2.5.4 The effect of DRX during hot work on Mg alloys...22
2.6 Corrosion behavior...24
CHAPTER Ⅲ
EXPERIMENTAL PROCEDURES...26
3.1 Materials preparation...26
3.2 Rolling and thermomechanical treatment...27
3.3 Microstructure and properties examination...28
3.3.1 Microstructural examination...28
3.3.2 Differential scanning calorimeter measurement...29
3.3.3 X-ray Diffraction (XRD) Measurement...29
3.3.4 Superplasticity test...30
3.4 Corrosion behavior...30
3.4.1 Polarization curve...30
3.4.2 Immersion test...31
3.5 Oxidation test...32
CHAPTER Ⅳ
RESULTS AND DISCUSSION...33
4.1 DSC measurement...33
4.2 Microstructure observation...34
4.3 X-ray Diffraction (XRD) Measurement...35
4.4 Microhardness...36
4.5 Tensile property...37
4.6 Oxidation test...41
4.7 Polarization curve and Immersion test...41
CHAPTER Ⅴ
CONCLUTIONS...45
REFERENCES...48

[1] A. Lasraoui and J.J. Jonas, Metall. Trans., 22A (1991) pp. 1545-1558.
[2] Y. Kojima, Materials Science Forum, 350 (2000) pp. 3-18.
[3] S. Nemoto, Handbook of Advanced Magnesium Technology, Kallos Puishing Co., Tokyo, (2000) pp. 2.
[4] H. Haferkamp, R. Boehm, U. Holzkamp, C. Jaschik, V. Kaese and M. Niemeyer, Materials Transactions, 42 (2001) pp. 1160-1166.
[5] P. Metenier and G. Gonzalez-Doncel, Materials Science and Engineering, 125A (1990) pp. 195-202.
[6] K. Matuzawa, T Koshihara, and Y. Kojima, J. Jpn. Inst. Light Met., 39 (1989) pp. 45-51 (in Japanese).
[7] J.Y. Wang, W. P. Hong, P.C. Hsu, C.C. Hsu and S. Lee, Materials Science Forum, 419-422 (2003) pp. 165-170.
[8] A.Yamamoto, T. Ashida, Y.Kouta, K.B. Kim, S. Fukumoto and H. Tsubakino, Materials. Transactions., 44 (2003) pp. 619-624.
[9] A. A. Nayeb-Hashemi, J. B. Clark and A. D. Pelton, Bull. Alloy Phase Diagrams 5 (1984) pp. 365.
[10] K. A. Munroe, Metal Progress 90 (1966) pp. 89.
[11] J. H. Jackson, P.D. Frost, A. C. Loonam, L. W. Eastwood and C. H. Long Trans. AIME, 185 (1949) 149.
[12] A. Saia and R. E. Edelman, Foundry, 90 (1962) 38.
[13] A. Saia, R. E. Edelman and H. L. Gilmore, Modern Casting, 52 (1967) pp. 105.
[14] A. Saia and R. E. Edelman, Modern Casting, 53 (1968) 165.
[15] W. R. D. Jones and G. V. Hogg, J. Inst. Me!, 85 (1957) pp. 255.
[16] C. V. Raynor, The physical metallurgy of magnesium and its alloys (London: Pergamon Press), (1959).
[17] J. C. McDonald, Trans. ASM, 61 (1968) pp. 505.
[18] J. C. McDonald, J. Inst. Met., 97 (1969) pp. 353.
[19] A. Alamo and A. D. Banchik, J. Mater. Sci., 15 (1980) pp. 222.
[20] A. A. Kazakov, M. A. Timonova and L. G. Borisova, Met. Sci. Heat Treat. (USSR), 25 (1983) pp. 682.
[21] R. Kh Kalimullin and Yu Ya Kozhevnikov, Met. Sci. Heat Treat. (USSR), 27 (1985) pp. 272.
[22] R. Kh Kalimullin and A. T. Berdnikov, Prot. Met. (USSR), 22 (1986) pp. 223.
[23] S. Das and H. L. Frascr, Proc. Of light weight alloys for aerospace applications (eds) E. W. Lee, E. H. Chia and N. J. Kim (Warrendate, Pa: TMS), (1989) pp. 151
[24] R. J. Jackson and P. D. Frost, NASA-SP-5068 (Washington DC: Office of Technology Utilization Division, NASA), (1967).
[25] P. D. Frost, et al., Aging Characteristics of Magnesium-Lithium Base Alloys, Trans. AIME, 188 (1950) pp. 1277.
[26] L. S. Darken and R. W. Gurry, Physical Chemistry of Metals, McGraw-Hill Book Company, New York (1953).
[27] J. H. Jackson, et al., Magnesium-Lithium Base Alloys - Preparation,
Fabrication, and General Characteristics, Trans. AIME, 188 (1949) pp. 149.
[28] P. Gordon, Trans. AMIE, 203 (1955) pp. 1043.
[29] Courtney, Mechanical behavior of materials pp. 313-314.
[30] Taku Sakai, Dynamic recrystallization microstructures under hot working conditions, Journal of Materials processing Technology 53 (1335) pp. 349-361.
[31] W. Roberts and B. Ahlblom, Acta metall., 26 (1978) pp. 801.
[32] Jazaeri and Humphreys, The transition from discontinuous to continuous recrystallization in some aluminium alloys II – annealing behavior, Acta Materialia 52 (2004) pp. 3251-3262.
[33] T. V. Cherian, P. Pietrokowsky and J. E. Dorn, Trans. Met. Soc. AIME, 185 (1949) pp. 948.
[34] C. M. Sellars and W. J. McG. Tegart, Int. Met. Rev., 17 (1972) pp. 1-24.
[35] A. Galiyev, R. Kaibyshev and G. Goitstein, "Correlation of Plastic Deformation and Dynamic Recrystallization in Magnesium Alloy ZK 60", Acta Mater, 49 (2001) pp. 1199-1207.
[36] O. Sitdikov and R. Kaibyshev, "Dynamic Recrystallization in Pure Magnesium", Materials Transaction, 42 (2001) pp. 1928-1937.
[37] O. Sitdikov, R. Kaibyshev and T. Sakai, "Dynamic Recrystallization Based on Twinning in Coarse-grained Mg", Materials Science Forum 419-422 (2003) pp. 521-526.
[38] R. S. Busk et al., Trans. AIME, 188 (1950) pp. 945.
[39] F. E. Hauser et al, Trans. ASM, 50 (1958) pp. 856.
[40] N. N.: Magnesium and Magnesium Alloys, Ullmann’s Encyclopedis of Industrial Chem istry, Reprint of Articles froms 5th Edition, VCH, Weingeim, 1990.
[41] C. M. Sellars and W. J. McG. Tegart, Int. Met. Rev., 17 (1972) pp. 1-24.
[42] H. Mecking and G. Gottstein, Recrystallization of Metallic Materials, F. Haessner eds., Dr. Reidereer Verlag, Suttgart, (1997) pp. 195-212.
[43] H. J. McQueen and J. J. Jonas, J. Appl. Metal Work., 3 (1984) pp. 233-241.
[44] T. Sheppard, Proc. 8th Light Metal Congress, J. Jeglitsch et al. eds., The University, Leoben, (1987) pp. 301-311.
[45] H. J. McQueen, E. Evangelista and J. Czech, Phys., B38 (1988) pp. 359-372.
[46] H. J. McQueen and J. J. Jonas, Al Alloys ’90 (the 2nd Intl. Conf. Beijing), (1990) pp. 727-742.
[47] H. J. McQueen and M. E. Kassner, Superplasticity in Aerospace II, T. R. McNelley eds., TMS-AIME, Warrendale, PA (1991) pp. 189-206.
[48] H. J. McQueen, E. Evangelista, M. E. Kassner, Z. Metalkde., 82 (1991) pp. 336-345.
[49] H. J. McQueen, Hot deformation of Aluminium Alloys, T. G. Langdon et al. eds., TMS-AIME, Warrendale, PA (1991) pp. 31-54.
[50] H. J. McQueen, Mat. Sci. Eng., A101 (1987) pp. 149-160.
[51] T. Sakai and J. J. Jonas, Acta Metal., 32 (1984) pp. 189-209.
[52] W. Roberts, Strength of Metals and Alloys (ICSMA7), H. J. McQueen etc. eds., Pergamon press, Oxford, U.K., (1986) pp. 1859-1892.
[53] H. J. McQueen, E. Evangelista, N. D. Ryan, Recrystallization (’90) in Metals and Materials, T. Chandra eds., TMS-AIME, Warrendale, PA (1990) pp. 89-100.
[54] T. G. Langdon, Metall. Trans., 13A (1982) pp. 689.
[55] M. Mabuchi, T. Asahina, H. Iwasaki, and K. Higashi, Mater sci. technol., 13 (1997) pp. 825.
[56] K. Kubota, M. Mabuchi and K. Higashi, J. Mater. Sci., 34 (1999) pp. 2255.
[57] M. Mabuchi, T. Mohri, N. Saito, M. Nakamura, H. Iwasaki and K. Higashi, in The 3rd Pacific Rim Interational Conference on Advanced Materials and Proceeding (PRICM3), ed. M. A. Imam, R. DeNale, S. Hanada, Z. Zhong and D. N. Lee., The Minerals, Metals and Materials Society, Honolulu, HI, (1998) pp. 1813.
[58] M. Mabuchi, K. Ameyama, H. Iwasaki and K. Higashi, Acta. Mater., 47 (1999) pp. 2047.
[59] A. Bussiba, A. Ben Artzy, A. Shtechman, S. Ifergan and M. Kupiec, Mater. sci. eng., A302 (2001) pp. 56-62.
[60] T. Mohri, M. Mabuchi, M. Nakamura, Asahina, H. Iwasaki, T. Aizawa and K. Higashi, Mater. Sci. eng., A290 (2000) pp. 139-144.
[61] Xin Wu, Yi Liu, Scripta Matrialia, 46 (2002) pp. 269-274.
[62] O. Ro I. S. Sivakesavam and Y. V. R. K. Prasad, Mater. Sci. Technol., 9 (1993) pp. 805.
[63] F. J. Himphreys and M. Hatherley, in Recrystallization and Related Annealing Phenomena. Pergamon Press, Oxford, (1996) pp. 363.
[64] H. Miura, H. Aoyama and T. J. Sakai, Japan Inst. Met.,58 (1994) pp. 269.
[65] A. Belyakov, H. Miura and T. Sakai, Mater. Sci. Eng.,A255 (1998) pp. 139.
[66] R. O. Kaibyshev and O. S. Sitdikov, Phys. Met. Metallogr.,78 (1994) pp. 420.
[67] A. Galiev and R. Kaibyshev, to be published.
[68] R. O. Kaibyshev and O. S. Sitdikov, Phys. Met. Metallogr.,73 (1992) pp. 635.
[69] S. E., Humphreys, F. J. and S. H. White, Acta metal., 30 (1982) pp. 1909.
[70] A. Belyakov and R. Kaibyshev, Nanostruct. Mater.,6 (1995) pp. 863.
[71] G. Gottstein, L. Chang and H. F. Yung, Mater. Sci. Technol., 7 (1991) pp. 158.
[72] G. Gottstein, and U. F. Kocks, Acta metal.,31 (1983) pp. 175.
[73] A. Galiev, R. Kaibyshev and O. Sitdikov, Nanostruct. Mater., 6 (1995) pp. 621.
[74] A. Mwembela, E. B. Konopleva and H. J. McQueen, Scripta Mater. 37 (1997) pp. 1789.
[75] R. O. Kaibyshev and Z. Sitdikov, Metalled, 85 (1994) pp. 738.
[76] J. C. Tan and M. J. Tan, Scripta Materialia, 47 (2002) pp. 101-106.
[77] J. C. Tan and M. J. Tan, Mater. Sci. eng., A339 (2003) pp. 81-89.
[78] H.C. Lin, K.M. Lin, H.M. Lin, C.H. Yang and M.T. Yeh, Magnesium Technology, (2005) pp. 275.
[79] H. Haferkamp, U. Juchmann and P. Kaese, et al., Magnesium Technology 2000 as held at the 2000 TMS Annual Meeting, (2000) pp. 101-106.
[80] Y. Wang, "Beitrag zur Verbesserung korrosiver Eigenschaften von superleichten Magnesium-Lithium-Legierungen Contribtrtions to the Enhancement of the Corrosive Properties of Superlight Magnesium- Lithium-Alloys" (Ph.D. thesis, Hanover University, Germany, 1997).
[81] C. R. Chakravorty, Bull. Mater. Sci. (India), 17 6 (1994) pp. 733-745.