鎂合金已廣泛使用於汽車產業、自行車架、航太發展與電子資訊3C產品等等。對於如何改善材料的機械性質是非常重要的課題，其中可以藉由晶粒細化的方式來達成目的。要達到晶粒細化的效果主要是透過材料在熱間加工的過程產生動態再結晶粒，本研究採用多道次熱間壓延的方法，期望讓鎂合金ZK60板材厚度可以達到較大的壓縮量，並獲得較細小的晶粒，以提高機械性質。
研究首先採用文獻已建立之再結晶預測式做為依據，使用有限元素分析軟體DEFORM對板材做較大壓下率50%的多道次熱間壓延模擬，探討其多道次間的差異與預測晶粒尺寸之變化。之後進行多道次熱間壓延實驗，以金相實驗觀察壓延後的晶粒組織，與模擬解析結果做比較，驗證其適用性，並對壓延材做機械性質之探討。

Magnesium alloys have been widely used in the automotive industry, bicycle frame, aerospace development and electronic information 3C products and so on. It is an important topics to improve the mechanical properties of the material, and the way of grain refining can be achieved the purpose. In this study, in order to make grain refinement, we applied plastic deformation in multi-pass hot rolling to let the dynamic recrystallization (DRX) be growth in the magnesium alloy sheets. It is expected that the thickness of the magnesium alloy ZK60 sheets can achieve a large reduction and get refined grain size to make the product have better mechanical properties.
The research is based on the recrystallization prediction that has been established in the literature, and to discuss the difference in the multi-pass hot rolling simulation for reduction 50% of magnesium alloy sheets which is carried on in FEM software DEFORM-2D. Then, this study makes multi-pass hot-rolling experiment and the metallographic microstructure observation to compare the same process conditions of FEM solutions to verify the correctness of the simulation, as well as do the discussion of mechanical properties.

Keywords: Multi-pass hot rolling, recrystallization prediction, dynamic recrystallization, microstructure, grain size

目錄
論文審定書 ....................................................................................................................... i
致謝 .................................................................................................................................. ii
摘要 ................................................................................................................................. iii
Abstract ............................................................................................................................ iv
目錄 .................................................................................................................................. v
圖目錄 ........................................................................................................................... viii
表目錄 ............................................................................................................................ xii
符號說明 ....................................................................................................................... xiii
第一章 緒論 .............................................................................................................. 1
1.1 前言 .................................................................................................................... 1
1.2 鎂合金的特性與應用 ........................................................................................ 2
鎂合金的用途 ........................................................................................ 2
添加不同元素對鎂合金的影響 ............................................................ 2
1.3 熱間壓延 ............................................................................................................ 4
壓延原理 ................................................................................................ 4
熱間壓延過程中的晶粒變化 ................................................................ 4
1.4 文獻回顧 ............................................................................................................ 5
鎂合金等壓延之相關文獻 .................................................................... 5
動態再結晶之相關文獻 ........................................................................ 6
多道次壓延之相關文獻 ........................................................................ 6
1.5 研究目的與本文架構 ........................................................................................ 7
第二章 多道次熱間壓延之有限元素解析 .............................................................. 9
2.1 模擬解析 ............................................................................................................ 9
模擬軟體 DEFORM 之介紹 ................................................................. 9
vi
2.2 鎂合金 ZK60 之塑流應力 ............................................................................... 10
2.3 動態再結晶之預測公式 .................................................................................. 12
塑流應力本構方程式 .......................................................................... 14
變形活化能 .......................................................................................... 14
動態再結晶體積百分比 ...................................................................... 16
峰值應變 .............................................................................................. 17
50%動態再結晶之應變 ........................................................................ 18
動態再結晶晶粒尺寸.......................................................................... 18
2.4 鎂合金板材熱間壓延的有限元素模式之建立 .............................................. 19
多道次熱間壓延模擬之基本假設 ...................................................... 19
模擬模型之建立 .................................................................................. 19
多道次熱間壓延模擬分析步驟 .......................................................... 22
第三章 鎂合金之多道次熱間壓延實驗 ................................................................ 23
3.1 前言 .................................................................................................................. 23
3.2 多道次熱間壓延實驗 ...................................................................................... 24
壓延設備規格說明 .............................................................................. 24
荷重計之校正 ...................................................................................... 25
輥輪之加熱方法 .................................................................................. 26
多道次熱間壓延實驗之規劃與步驟 .................................................. 27
3.3 鎂合金板材實驗前後之金相觀察 .................................................................. 28
第四章 模擬解析與實驗結果之討論 .................................................................... 32
4.1 多道次熱間壓延模擬解析 .............................................................................. 32
壓下率 50%四種道次之溫度與晶粒尺寸比較.................................. 32
4.2 套用實驗條件進行模擬解析並與實驗結果之比較 ...................................... 73
代入實驗條件進行一道次與二道次之模擬結果 .............................. 76
vii
一道次與二道次之實驗結果與解析結果之各數值比較 .................. 83
機械性質比較 ...................................................................................... 88
三道次與六道次之實驗 ...................................................................... 92
第五章 結論與未來展望 ........................................................................................ 94
5.1 鎂合金多道次熱間壓延有限元素分析 .......................................................... 94
5.2 鎂合金多道次熱間壓延實驗 .......................................................................... 94
5.3 未來展望 .......................................................................................................... 95
第六章 文獻 ............................................................................................................ 96
參考文獻 ................................................................................................................. 96

[1] Y. Chino, X. Huang, K. Mabuchi, “Enhancement of Stretch Formability at Room Temperature by Addition of Ca in Mg-Zn Alloy”, Master. Trans., Vol 51, pp.818-821 (2010).
[2] 陳勇宏，“AZ31及AZ61鎂合金之晶粒細化與鈑片成形研究”，國立中央大學機械工程研究所博士論文 (2004)。
[3] 陳炫翰，“鎂合金AZ31熱間壓延之相關研究”，國立中山大學機械與機電工程研究所碩士論文 (2015)。
[4] 金重勳，1995，機械材料，台南市：復文書局。
[5] 許源泉，2008，塑性加工學，台北縣土城市：全華圖書。
[6] K. Serope and S. Kalpakjian, Manufacturing Engineering and Technology: Addison Wesley Publishing Company, (1992).
[7] 橘木 順二， 田村 洋介，本保 元次郎，早田 博， Alexander McLean，“熱間圧延加工を施したMg-La-Zr合金の組織評価”，塑性と加工（日本塑性加工学会誌）第57巻，第661号（2016―2）。
[8] T.C. Chang, J.Y. Wang, C.M. O, S. Lee, “Grain refining of magnesium alloy AZ31 by rolling”, Journal of Materials Processing Technology 140, pp.588–591 (2003).
[9] 野田 雅史, 森 久史, 船見 国男, 権田 善史, “難燃性Mg - 10Al - 1Ca合金中板材の圧延加工による機械的特性の向上と組織”, 塑性加工春季講演会, (2014)。
[10] J. Su , M. Sanjari, A. Syed H. Kabir, John J. Jonas, S. Yue, “Static recrystallization behavior of magnesium AZ31 alloy subjected to high speed rolling”, Materials Science & Engineering A 662, pp.412–425 (2016).
[11] K. Yu, X.Y. Wang, Z.Y. Cai, R.C. Wang, D. Shi, “Finite Element Simulation of Deformation in Hot Rolling Process of AZ31 Magnesium Alloy”, Journal of Central South University, Vol.40, No.6, Dec. (2009).
[12] S. Aliakbari Sani, G.R. Ebrahimi, A.R. Kiani Rashid, “Hot deformation behavior and dynamic recrystallization kinetics of AZ61 and AZ61 + Sr magnesium alloys”, Journal of Magnesium and Alloys 4, PP.104–114 (2016).
[13] Y.Z. Wu, H.G. Yan, S.Q. Zhu, J.H. Chen, A.M. Liu, X.L. Liu, “Flow Behavior and Microstructure of ZK60 Magnesium Alloy Compression at High Strain Rate”, T. Nonferrous Met. Soc. China 24, pp. 930-939. (2014).
[14] 邱盈燕，王建義，“Mg-4.5﹪Al-1.5﹪Zn 之顯微組織與機械性質研究”，國立東華大學材料科學與工程學系 (2005)。
[15] 王斌，易丹青，方西亞，劉會群，吳春萍，“ZK60 镁合金高温動態再结晶行為的研究”，中南大學材料科學與工程學院,長沙。
[16] H.L. Ding, Kanamori, Honma, Kamado, Kojima, “ FEM Analysis for Hot Rolling Process of AM60 Alloy”, Trans. Nonferrous Met. Soc. China 18, s242−s246 (2008).
[17] S.Y. Yuan, L.W. Zhang, S.L. Liao, G.D. Jiang, Y.S. Yu, M. Qi, “Simulation of deformation and temperature in multi-pass continuous rolling by three-dimensional FEM”, Journal of Materials Processing Technology 209, pp. 2760–2766 (2009).
[18] C. Zheng, N. Xiao, D. Li, Y. Li, “Microstructure prediction of the austenite recrystallization during multi-pass steel strip hot rolling: A cellular automaton modeling”, Computational Materials Science 44, pp.507–514 (2008).
[19] H. Ding, K. Hirai, S. Kamado, “Microstructure characteristics during the multi-pass hot rolling and their effect on the mechanical properties of AM50 magnesium alloy sheet”, Materials Science and Engineering A 527, pp. 3379–3385 (2010).
[20] X. Wang, C. Yang, L. X. Hu, “Mechanical Properties and Isothermal Rolling Process of AZ31 As-cast Mg alloy Plate”, Materials Science and Technology, Vol 19, No.2 , ( 2011).
[21] R. Ma, Y. Zhao, Y. Wang, “Grain refinement and mechanical properties improvement of AZ31 Mg alloy sheet obtained by two - stage rolling”, Materials Science & Engineering A 691, pp.81–87 (2017).
[22] DEFORM Simulation http://www.deform.com/
[23] 葉佐倫，“鎂合金板材熱間壓延之微觀組織預測”，國立中山大學機械與機電工程研究所碩士論文 (2015)。
[24] Y.C.Lin, Ming-SongChen, JueZhong, “Prediction of 42CrMo steel flow stress at high temperature and strain rate”, Mechanics Research Communications, Volume 35, Issue 3, Pages 142-150 (April 2008).
[25] Y. S. Jang, D. C. Ko, B. M. Kim, ”Application of the Finite Element Method to Predict Microstructure Evolution in the Hot Forging of Steel”, Journal of Materials Processing Technology, 101(1/3): pp. 85−94 (2000).
[26] C.M. Sellars, “Basics of Modelling for Control of Microstructure in Thermomechanical Control Processing”, Ironmaking and Steelmaking, 22, pp. 459–464 (1995).
[27] T. Senuma, H. Yada, Y. Matsumura, and T. Futamura, “Structure of Austenite of Carbon Steels in High Speed Hot Working Processes”, Tetsu-to-Hagane, 70, pp.2112–2119 (1984).
[28] C.M. Sellars, W.J.M. Tegart, “On the Mechanism of Hot Deformation”, Acta Metall., vol. 14, no. 9, pp. 1136–1138 (1966).
[29] C.M. Zener, J.H.Hollomon, Jr,” Effect of Strain Rate Upon Plastic Flow of Steel”., J. Appl. Phys., 15, 22 (1944).