臺灣博碩士論文加值系統

為拓展鎂合金於運輸工具上之應用，需添加微量之稀土元素以幫助提升鎂合金之室溫及高溫機械性質，故本研究分別以富含La及Ce兩種不同之混合稀土元素熔配出Mg97Zn1(Mm-La)2與Mg97Zn1(Mm-Ce)2合金，再將其擠製成板材。常溫拉伸試驗結果顯示，兩合金材料在原擠製材狀態，降伏強度均可達到 300MPa以上，添加鑭元素因有較大的成分過冷而具有較小之晶粒，因此Mg97Zn1(Mm-La)2合金在強度的表現上優於Mg97Zn1(Mm-Ce)2合金；若在 473K之高溫拉伸試驗中，材料之降伏強度仍能具有 200MPa左右之強度。觀察兩者之顯微組織，並藉由奈米壓痕測試，皆可發現材料之二次相硬度高於鎂基材硬度約5倍，此為兩合金高強度之主因，強化機制屬於複合強化；經XRD及TEM分析結果得知，此類二次相與CeMg12及LaMg12結構相同，再經由EDS分析，二次相鑑定為(La,Ce)(Zn,Mg)12；另外，由高解析影像及繞射圖譜觀察得知，部分二次相內部有高密度的反向邊界(Anti-phase boundary)結構，且反向邊界沿著(001)排列。為繼續強化此兩種合金，將分別於 573K、 673K、 773K下施以 30%之加工量。降伏強度隨著軋延溫度升高而降低，主要係因回復及再結晶所致；然而我們發現在 773K之熱軋延下，兩合金的顯微組織會趨於相同，材料中之二次相會細化且分散，預期有散佈強化之效果，但結果則不然，實驗數據顯示兩合金經此高溫下熱軋延會導致回復及晶粒成長，長時間的加工造成材料間歇性退火成為材料強度下降的主因。將 773K熱軋延後的兩合金進行高溫拉伸測試，由數據顯示， 773K熱軋延 80%後在高溫拉伸的強度表現上優於原擠製材，由顯微組織推測，是由於熱軋延後晶界面積減少，再藉由分散且細化的二次相鎖住晶界，限制晶界的滑移而達到強化。

In order to extend the application of magnesium alloys in the automotive field, the room and elevated temperature strengths of rare-earth element added magnesium alloys were investigated. In this research, the Mg97Zn1(Mm-La)2 and Mg97Zn1(Mm-Ce)2 alloy billets were extruded into planes. According to the tensile results, both as-extruded alloys possess high tensile yield strength over 300 MPa. Besides, the high temperature tensile test at 473 K, result shows that both alloys still keep high yield strength of 200 MPa. According to the nano-indentation test result, the second phase has much higher hardness than matrix, the strengthening mechanisms were composite strengthening. In XRD and TEM results, both alloys comprise two phases of h.c.p.-Mg and (La,Ce)(Zn,Mg)12. Form the diffraction pattern and high resolution lattice image, the secondary orientation of phase was separated from matrix by anti-phase boundaries, and the anti-phase boundaries are parallel to the (001) plane of secondary phase.
The hot rolling with 30 % reduction at different temperatures of 573 K, 673 K and 773 K were performed. The tensile test results show that the yield strength decreases with increasing hot rolling temperature. The reason is due to the recovery and recrystallization of matrix during high temperature rolling. From the microstructure, the second phases were cracked and refined after hot rolling. The finer dispersion of second phase can be obtained at higher temperature rolling of 773 K. According to the high temperature tensile results, both alloys 80 % hot rolled at 773 K have better elevated temperature strengths than as-extruded. That means optimum high temperature mechanical properties will be achieved after higher rolling reduction.

摘要 Ⅰ
Abstract Ⅱ
總目錄 Ⅲ
表目錄 Ⅵ
圖目錄 Ⅶ
第一章 緒論 1
1-1 前言 1
1-2 研究動機 3
第二章 文獻回顧 5
2-1鎂合金簡介 5
2-2 合金元素的添加對鎂合金性質之影響 8
2-2-1 鋅(Zn)元素 8
2-2-2 稀土元素(Rare earth, Re) 9
2-2-2-1 稀土元素的介紹 9
2-2-2-2 稀土符號 10
2-2-3 稀土元素添加之影響 11
2-2-4 稀土鎂合金及其應用 12
2-2-4-1 Mg-Al-RE (AE系)合金 12
2-2-4-2 Mg-RE-Zr (EK系)合金 12
2-2-4-3 Mg-Y-RE (WE系)合金 13
2-2-4-4 Mg-Zn-RE (EZ系)合金 14
2-2-5 Mg-Zn-Y合金 14
2-2-6 Mg-Zn-Ce及Mg-Zn-La 合金 18
第三章 實驗方法 21
3-1 材料製備 21
3-1-1 鎂合金熔煉(Melting) 21
3-1-2 鎂合金板材擠製(Extrusion) 22
3-1-3 感應耦合電漿質譜分析儀(ICP-MS) 22
3-1-4 熱軋延製程(Hot rolling) 24
3-2 顯微組織觀察 26
3-2-1 光學顯微鏡(Optical microscope, OM)分析 26
3-2-2 掃描式電子顯微鏡(Scanning electron microscope,SEM)分析 28
3-3 機械性質分析 29
3-3-1 奈米壓痕硬度量測(Nano-indentation system) 29
3-3-2 拉伸測試 30
3-4結構分析 32
3-4-1 X光繞射( X-Ray diffraction, XRD)分析 32
3-4-2穿透式電子顯微鏡(Transmission electron microscope, TEM)分析 33
3-4-2-1 TEM試片製備 34
3-4-2-2 窩穴研磨機(Dimple Grinder) 35
3-4-2-3 離子薄化機 36
3-4-2-4 TEM 繞射圖譜分析 37
第四章 實驗結果 39
4-1Mg97Zn1(Mm-La)2,Mg97Zn1(Mm-Ce)2合金原擠製材 39
4-1-1 顯微組織觀察 39
4-1-2 X-ray 繞射圖譜分析 43
4-1-3 TEM分析 44
4-1-4 室溫機械性質分析 49
4-1-5 高溫機械性質分析 50
4-1-6 高溫拉伸破斷面觀察 53
4-2 Mg97Zn1(Mm-La)2, Mg97Zn1(Mm-Ce)2合金經恆溫熱軋延加工(不同溫度，相同總軋延率；573K、673K、773K-30%，每道次8%) 59
4-2-1 顯微組織觀察 59
4-2-2 機械性質分析 59
4-3 Mg97Zn1(Mm-La)2, Mg97Zn1(Mm-Ce)2合金經恆溫熱軋延加工(相同溫度，不同總軋延率；773K-30%、60%、80%，每道次8%) 62
4-3-1 顯微組織觀察 62
4-3-2 室溫機械性質分析 62
4-3-3 高溫機械性質分析 68
4-3-4 高溫拉伸破斷面觀察 71
第五章 結論 75
參考文獻 77

[1]廖銘枝、陳元隆，「鎂合金表面化學處理劑之應用演進」，鎂合金產業專欄，2004年2月24期。
[2]陳錦修，「鎂合金在汽車工業之應用」，鎂合金產業專欄-工業材料雜誌，2004年6月186期。
[3]蔡辛甫，「採用鎂合金材質的輕量化效果」，鎂合金產業通訊，2006年2月32期。
[4]邱垂泓，「鎂合金產業資訊」，鎂合金產業通訊-工業材料雜誌，2003年8月200期。
[5]H. Takuda, T. Yoshii and N. Hatta, Journal of Materials, 1999.
[6]K. Kubota, M. Mabuchi, K. Higashi, Journal of Materials science, 1999 .
[7]R. Alizadeh, R. Mahmudi, Mater. Sci. Eng. A 527 , 2010.
[8]L. L. Rokhlin,Structure and properties of alloys of the Mg-REM system, Metal Science and Heat Treatment ,2006,11, p.18-22
[9]翁仁斌， 「鎂合金固相回收之研究」，中華大學機械與航太工程研究所，2006，5月，碩士論文。
[10] 蔡辛甫，「鎂合金產業的現況與新發展」，工業材料雜誌，2009年2月266期。
[11]日本鎂合金協會，鎂合金基礎知識http://www.magnesium.or.jp/index.html
[12]鍾仕豪，「超輕镁理合金的拉伸與疲勞特性研究」，國立中央大學機械工程學系，2011年6月，碩士論文。
[13]王建義， 「鎂合金板材之壓型 (Press Forming) 加工技術」，鎂合金產業專欄，2001年2月。
[14]陽俊彬，「鎂合金之鍛造製程與外殼段件研究開發」，鎂合金產業專欄，2005年2月。
[15]Shahzad M, Wagner L. Microstructure development during extrusion in a wrought Mg–Zn–Zr alloy. Scripta Mater , 2009.
[16]Shepeleva L, Bamberger M. Microstructure of high pressure die cast AZ91D modified with Ca and Ce. Mater Sci Eng A , 2006.
[17]Kleiner S, Beffort O, Uggowitzer PJ. Microstructure evolution during reheating of an extruded Mg–Al–Zn alloy into the semisolid state. Scripta Mater , 2004.
[18]Zheng MY, Wu K, Liang M, Kamado S, Kojima Y. The effect of thermal exposure on the interface and mechanical properties of Al18B4O33w/AZ91 magnesium matrix composite. Mater Sci Eng A , 2004.
[19]鄭子樵、李紅英，新材料與應用技術叢書「稀土功能材料」，2006.
[20]T.E. Leontis, in F.H. Spedding and A.H. Daane (eds.), The Rare Earths, Wiley & Sons, New York, 1961.
[21]Sakkinen, D. J.(1994).SAE Paper 940779.
[22]SU Gui-hua, ZHANG Liang, CHENG Li-ren, LIU Yong-bing, CAO Zhan-yi. Microstructure and mechanical properties of Mg-6Al-0.3Mn-xY alloys prepared by casting and hot rolling. Transactions of Nonferrous Metals Society of China, 2010.
[23]M.O. Pekguleryuz, A.A. Kaya, Adv. Eng. Mater.5, 2003.
[24]Moreno, I. P., Jones, J.E., in preparation.
[25]Powell, B. R., Rezhets, V., Balogh, M. P., & Waldo, R. A. (2001). In J. Hryn(Ed.). Magnesium Technology 2001. The Minerals, Metals and Materials Society, Warrendale, PA.
[26]Die castability and property evaluation of AE alloys for drive train components, in: Proceedings of the 13th Magnesium Automotive and End User Seminar, Aalen, akke , 2005 B.
[27]K. Maruyama, M. Suzuki, H. Sato, Metall. Mater. Trans. A 33, 2002.
[28]L. Gao, R.S. Chen, E.H. Han, J. Alloys Compd. 472, 2009.
[29]B . L . M ORDIKE and W . HENNING , in “Proc. Magnesium Technology,” edited by C. Baker (The Institute of Metals, London,1987).
[30]H . KARIM ZADEH , J . M . W ORRALL , R . PILKINGTON and G . W . LORIM ER , in “Proc. Magnesium Technology,” edited by C. Baker (The Institute of Metals, London, 1987).
[31]T . M OHRI , M . M ABUCHI , N . SAITO and M .NAKAM URA , Mater. Sci. Eng. A257 , 1999.
[32]Y. Kawamura, K. Hayashi, A. Inoue, T. Masumoto, Rapidly Solidifield Powder Metallurgy Mg97Zn1Y2 Alloys with Excellent Tensile Yield Strength above 600MPa. Materials Transactions, 2001.
[33]Akihisa Inoue, Y. Kawamura, M. Matsushita, K. Hayashi, J. Koike .Nove1 hexagonal structure and ultrahigh strength of magnesium solid solution in the Mg-Zn-Y system [J ].Mater Res Soc, 2001.
[34]Minoru Nishida, Yoshihito Kawamura, Takateru Yamamuro, Formation process of unique microstructure in rapidly solidified Mg97Zn1 Y2 alloy, Materials Science and Engineering A 375–377 (2004) 1217–1223.
[35]T Itoi, T. Seimiya, Y. Kawamura, M. Hirohashi. Longer period stacking structures observed in Mg97Zn1Y2 alloy[J]. Scr Mater,2004.
[36]Kenji Amiya, Tetsu Ohsuna, Akihisa Inoue. Long-Period Hexagonal Structures in Melt-Spun Mg97Ln2Zn1(Ln=Lanthanide Metal) Alloys. Materials Transactions, Vol. 44, No. 10 , 2003.
[37]K. HAGIHARA, A. KINOSHITA, Y. SUGINO, M. YAMASAKI, Y. KAWAMURA,H.Y. YASUDA, Y. UMAKOSHI, Plastic deformation behavior of Mg97Zn1Y2 extruded alloys. Trans. Nonferrous Met. Soc. China 20, 2010.
[38]M. Yamasaki, K. Hashimoto, K. Hagihara, Y. Kawamura, Effect of multimodal microstructure evolution on mechanical properties of Mg–Zn–Y extruded alloy. Acta Material 59 , 2011.
[39]Yoshihito Kawamura and Michiaki Yamasaki Formation and Mechanical Properties of Mg97Zn1RE2 Alloys with Long-Period Stacking Ordered Structure Materials Transactions, Vol. 48, No. 11 ,2007.
[40]Y. Kawamura, T. Morisaka and M. Yamasaki Structure and Mechanical Properties of Rapidly Solidified Mg97Zn1RE2 Alloys Mater. Sci. Forum 419-422 , 2003.
[41]B. I. Bondarev and L. L. Rokhlin, “Metal science tendencies concerning the development of magnesium-base materials,” in: Fundamental Problems of Russian Metallurgy at the Dawn of the XXI Century, Vol. 2 [in Russian], Russian Academy of Natural Sciences. Dep. of Metallurgy, Moscow ,1998 .
[42]劉楚明、朱秀榮、周海濤，鎂合金相圖集，2006年。
[43]Robert E. Reed-hill, Physical metallurgy principles.
[44]T.L. Chia, M.A. Easton, S.M. Zhu, M.A. Gibson, N. Birbilis, J.F. Nie, The effect of alloy composition on the microstructure and tensile properties of binary Mg-rare earth alloys, Intermetallics 17 , 2009.
[45]M. Nishijima, K. Hiraga, T. Itoi and M Hirohashi, One-Dimensional Anti-Phase Structures Based on an Mg12Ce (Mn12Th-Type)Structure in an Mg91Ce6Zn3 Alloy, Studied by High-Resolution Transmission Electron Microscopy and High-Angle Annular Detector Dark-Field Scanning Transmission Electron Microscopy, Materials Transactions, Vol, No. 3, 2006.
[46]余琨、黎文獻、張世軍，Ce對鎂及鎂合金中晶粒的細化機理，稀有金屬材料與工程，Vol.34, No.7 July 2005.
[47]袁付慶、張靜、方超，稀土元素對鎂合金晶粒細化的研究，材料熱處理技術，2011年。
[48]S. Golmakaniyoon, R. Mahmudi, omparisonof the effects of La- and Ce-rich rare earth additions on themicrostructure, creep resistance, and high-temperature mechanical properties of Mg–6Zn–3Cu cast alloy, Materials Science and Engineering A, 528 , 2011 .
[49]LE Qi-chi, ZHANG Zhi-qiang, SHAO Zhi-wen, CUI Jian-zhong, XIE Yi, Microstructures and mechanical properties of Mg-2%Zn-0.4%RE alloys, Transactions of Nonferrous Metals Society of China, 2010.
[50]M. MABUCHI and K. HIGASHI, STRENGTHENING MECHANISMS OF Mg-Si ALLOYS, Acta mater. Vol. 44, No. 11. pp. 4611- 4618, 1996.
[51]K.KUBOTA, M. MABUCHI, K. HIGASHI, Review process and mechanical properties of fine-grained magnesium alloys, Journal of materials science 34, 1999.