跳到主要內容

簡易檢索 / 詳目顯示

回結果列表
研究生： 陳學億
Hsueh-I Chen
論文名稱： 半固態鎂合金流動行為之研究分析
The Research of the Flow Behavior of the Semi-Solid State Magnesium Alloy
指導教授： 陳志臣
Jyh-Chen Chen
口試委員:
學位類別： 博士
Doctor
系所名稱： 工學院 - 機械工程學系
Department of Mechanical Engineering
畢業學年度： 97
語文別： 中文
論文頁數： 117
中文關鍵詞： 鎂合金 、半固態 、流動行為
外文關鍵詞： Magnesium Alloy, Semi-Solid State, Flow Behavior
相關次數： 點閱：11  下載：0 
分享至:
查詢本校圖書館目錄 查詢臺灣博碩士論文知識加值系統 勘誤回報

    • 研究的目的在於探討鎂合金AZ91D在半固態時的流動行為。實驗中，利用可在高溫下量測黏度的同心圓柱黏度計，觀測半固態鎂合金黏漿的視黏度與剪應變和溫度之間的關係。由實驗結果發現，黏漿的視黏度隨著溫度的上升而降低，隨著剪應變率的增加而減少，具有剪變薄流體的特性。並根據本實驗數據，知道數學冪次式中的n值為接近於0.84。鎂合金AZ91D半固態黏漿觸變程度會隨著恆定剪應變率作用時間的增加而變大，但是，剪應力減少比例的曲線會越趨平緩，因為晶粒被球化至一定程度之後，更長的恆定剪應變率作用時間對剪應力將不會有顯著的影響。長時間的攪拌效應會讓視黏度先減少後逐漸增加，由於內部結構從樹枝狀結構破壞成顆粒較小的非樹枝狀結構，晶粒尺寸也會跟著減少，隨著攪拌時間的持續增加，晶粒會因為粗化效應逐漸長大，尺寸也會逐漸增大。不同的固相分率、預先攪拌時間與停留時間對流動性質也會產生影響，當預先攪拌時間固定時，較高固相分率的視黏度會隨著停留時間的增加而增加，這是由於顆粒聚合主導粗化機制並讓包覆液體維持在晶粒裡面；較低固相分率的視黏度會隨著停留時間的增加而減少，因為晶粒內部的包覆液體會藉由奧斯特瓦爾德成長主導的粗化作用被釋放，這將會導致流動性變佳。當固相分率固定時，較短預先攪拌時間的視黏度會隨著停留時間的增加而增加，較長預先攪拌時間的視黏度會隨著停留時間的增加而減少，這都是因為顆粒聚合與奧斯特瓦爾德成長等粗化機制對包覆液體產生不同影響所導致流動性的變化。

    In this study, the flow behavior of the semi-solid AZ91D magnesium alloy is investigated by a high-temperature coaxial-cylinder viscometer. The relations between the steady-state apparent viscosity, shear rate and temperature of the magnesium alloy are observed. According to the results, the apparent viscosity decrease as the isothermal temperature and shear rate increase. The semi-solid AZ91D magnesium alloy shows the shear-thinning behavior. Basing on the experimental data, the power-law constant n is around 0.84. As the shearing time of maintained shear rate increase, the thixotropic behavior of magnesium slurry is more obvious. But the curve of reducing ratio is gradual, and the longer shearing time of maintained shear rate would not affect the shear stress. As the stirring time increases, the apparent viscosity initially decreases, and then it follows increasing curve. It is because that the dendritic structure is destroyed into the smaller non-dendritic one. As the stirring time continuously increases, the coarsening effect causes the particle size to increase. The solid fraction, pre-stirring time and resting time have influence on the flow behavior. When the pre-stirring time is fixed, the apparent viscosity increases as the resting time increases at high solid fraction. At the low solid fraction, the apparent viscosity decreases as the resting time increases. When the solid fraction is fixed, the apparent viscosity increases for shorter pre-stirring time as the resting time increases, and the apparent viscosity decreases for longer pre-stirring time as the resting time increases.

    目錄 頁碼 中文摘要.........................................................................................................................i 英文摘要........................................................................................................................ii 誌謝...............................................................................................................................iii 符號說明.......................................................................................................................iv 目錄................................................................................................................................v 表目錄.........................................................................................................................viii 圖目錄...........................................................................................................................ix 第一章 緒論..............................................................................................................1 1.1 背景.........................................................................................................................1 1.2 文獻回顧.................................................................................................................2 1.3 研究動機.................................................................................................................3 1.4 研究目的.................................................................................................................4 1.5 研究方法.................................................................................................................5 圖....................................................................................................................................9 第二章 理論基礎...................................................................................................17 2.1 凝固結構...............................................................................................................17 2.2 半固態材料成形之原理.......................................................................................18 2.3 半固態材料之流動特性.......................................................................................20 2.3.1 固相分率對流動的影響................................................................................21 2.3.2 晶粒形狀對流動的影響................................................................................22 2.3.3 包覆液體對流動的影響................................................................................22 2.3.4 攪拌因素對流動的影響................................................................................22 2.3.5 時間因素對流動的影響................................................................................23 2.4 半固態材料的觸變行為.......................................................................................24 2.5 鎂合金AZ91D的流變特性..................................................................................24 圖..................................................................................................................................27 第三章 實驗設備與流程.....................................................................................46 3.1 實驗設備...............................................................................................................46 3.1.1 實驗材料........................................................................................................46 3.1.2 傳動感應系統................................................................................................48 3.1.3 測矩系統........................................................................................................49 3.1.4 恆溫系統........................................................................................................50 3.2 實驗流程...............................................................................................................50 3.2.1 穩態實驗........................................................................................................51 3.2.2 觸變實驗........................................................................................................51 3.2.3 暫態實驗........................................................................................................51 3.2.4 攪拌時間之影響............................................................................................52 3.2.5 固相分率、預先攪拌時間與停留時間之影響............................................52 圖表..............................................................................................................................53 第四章 結果與討論..............................................................................................67 4.1 半固態溫度及剪應變率對鎂合金黏漿穩態流動的影響...................................67 4.1.1 由冪次數學式觀察鎂合金黏漿的穩態流動.................................................68 4.1.2 實驗結果與其他文獻作比較.........................................................................69 4.2 鎂合金AZ91D的觸變行為.................................................................................70 4.2.1 不同剪應變率對鎂合金AZ91D觸變行為的影響.......................................71 4.2.2 剪應變率改變速率對鎂合金AZ91D觸變行為的影響...............................72 4.2.3 不同恆定剪應變率作用時間對鎂合金AZ91D觸變行為的影響...............72 4.2.4 鎂合金AZ91D觸變行為的分析...................................................................73 4.3 鎂合金AZ91D的暫態行為.................................................................................73 4.3.1 剪應變率的瞬間改變對鎂合金AZ91D暫態行為的影響...........................74 4.3.2 鎂合金AZ91D暫態行為的分析...................................................................75 4.4 攪拌時間之效應...................................................................................................75 4.5 鎂合金AZ91D固相分率、預先攪拌時間與停留時間之影響.........................77 4.5.1 固定預先攪拌時間，不同固相分率與停留時間之影響.............................77 4.5.2 固定固相分率，不同預先攪拌時間與停留時間之影響.............................78 圖..................................................................................................................................80 第五章 結論..........................................................................................................109 5.1 穩態流動.............................................................................................................109 5.2 觸變行為.............................................................................................................109 5.3 暫態行為.............................................................................................................110 5.4 攪拌時間之效應.................................................................................................110 5.5 固相分率、預先攪拌時間與停留時間之影響.................................................111 5.6 實驗設備之設計與改良.....................................................................................111 參考文獻.................................................................................................................113 表目錄 頁碼 表3-1 鎂合金AZ91D的化學組成(wt%)..................................................................53 表3-2 鎂合金AZ91D的物理性質............................................................................54 圖目錄 頁碼 圖1-1 三種主要鑄造方法的流程圖............................................................................9 圖1-2 半固態射出成型機之示意圖[6].....................................................................10 圖1-3 半固態黏漿視黏度與模具充填速度關係圖[7].............................................11 圖1-4 鎂鋁合金二元相圖[4].....................................................................................12 圖1-5 毛細管黏度計示意圖[10]...............................................................................13 圖1-6 落球黏度計示意圖[10]...................................................................................14 圖1-7 擠製法黏度計示意圖......................................................................................15 圖1-8 同心圓柱黏度計示意圖..................................................................................16 圖2-1 熔液為正溫度梯度時對固液界面生長的影響[18].......................................27 圖2-2 固液界面的生長(a)平面生長(b)樹枝狀生長[18]..........................................28 圖2-3 熔液為負溫度梯度時對固液界面生長的影響[18].......................................29 圖2-4 二元相圖之偏析效應分析[18].......................................................................30 圖2-5 組成過冷在固液界面凝固處的原由(a)偏析效應造成熔液濃度的不均勻(b)熔液濃度不均勻造成平衡凝固溫度為曲線而與熔液溫度線形成組成過冷[18]...31 圖2-6 不同組成過冷程度對固液界面的影響[18]...................................................32 圖2-7 溫度對合金壓縮變形阻抗的影響..................................................................33 圖2-8 晶粒結構(a)樹枝狀結構(b)球狀結構[2]........................................................34 圖2-9 半固態材料不同固相分率示意圖[2].............................................................35 圖2-10 半固態金屬的流動機制................................................................................36 圖2-11 不同結構的碰撞及結合所產生包覆液體的影響(a)樹枝狀結構(b)球狀[11]...............................................................................................................................37 圖2-12 攪拌對晶粒結構破壞的演化過程[2]...........................................................38 圖2-13 不同固相分率的剪應變率與視黏度關係圖[16].........................................39 圖2-14 Joly等人[14]實驗流程圖...............................................................................40 圖2-15 錫鉛合金黏漿的遲滯現象[14] ....................................................................41 圖2-16 各種觸變性流體的剪應力與剪應變率關係圖(a)假塑性的觸變性流體(b)牛頓性的觸變性流體(c)塑性的觸變性流體(d)黏塑性的觸變性流體[10]..............42 圖2-17 剪應力與剪應變率關係圖[19].....................................................................43 圖2-18 AZ91D的流變鑄造演化過程[17] .................................................................44 圖2-19 Ghosh等人[4]所架構的同心圓柱黏度計.....................................................45 圖3-1 實驗設備示意圖..............................................................................................55 圖3-2 傳動感應系統之內外坩堝尺寸圖..................................................................56 圖3-3 各種材質的坩堝(a)SKD61鋼材(b)石墨材質................................................57 圖3-4 荷重元的樣式與尺寸圖..................................................................................58 圖3-5 訊號放大器的規格與尺寸圖..........................................................................59 圖3-6 滾珠式軸承......................................................................................................60 圖3-7 加熱爐(a)示意圖與(b)實體圖.........................................................................61 圖3-8 穩態實驗流程圖..............................................................................................62 圖3-9 觸變實驗流程圖..............................................................................................63 圖3-10 暫態實驗流程圖............................................................................................64 圖3-11 攪拌時間實驗流程圖....................................................................................65 圖3-12 固相分率、預先攪拌時間與停留時間實驗流程圖....................................66 圖4-1 溫度及剪應變率與鎂合金黏漿視黏度的關係圖..........................................80 圖4-2 在不同剪應變率下，固相分率與視黏度值的關係圖..................................81 圖4-3 在不同固相分率下，剪應變率與視黏度的對數關係圖..............................82 圖4-4 固相分率與冪次式中的n值關係圖..............................................................83 圖4-5 研究結果與文獻的視黏度值比較..................................................................84 圖4-6 實驗過後的內圓錐照片(a)整支(b)前段(c)後段.............................................85 圖4-7 不同剪應變率的觸變行為結果......................................................................86 圖4-8 不同剪應變率改變速率的觸變行為結果......................................................87 圖4-9 不同恆定剪應變率作用時間的觸變行為結果..............................................88 圖4-10 不同恆定剪應變率作用時間的最低剪應力與減少比例............................89 圖4-11 不同剪應變率的暫態行為結果(驟升).........................................................90 圖4-12 不同剪應變率的暫態行為結果(驟降).........................................................91 圖4-13 不同固相分率的暫態行為結果(驟升).........................................................92 圖4-14 不同固相分率的暫態行為結果(驟降).........................................................93 圖4-15 半固態合金剪應變率與剪應力示意圖by H. Peng[34]..............................94 圖4-16 視黏度與攪拌時間關係圖............................................................................95 圖4-17 晶粒結構發展示意圖....................................................................................96 圖4-18 不同攪拌時間的SEM圖(a)10 (b)20 (c)40 (d)90 (e)120(分鐘)...................97 圖4-19 晶粒尺寸與攪拌時間的關係圖....................................................................98 圖4-20 不同固相分率下，視黏度與停留時間關係圖............................................99 圖4-21 晶粒結構發展示意圖..................................................................................100 圖4-22 高固相分率不同停留時間的SEM圖(a)10(b)40(c)90(min)......................101 圖4-23 低固相分率不同停留時間的SEM圖(a)10(b)40(c)90(min)......................102 圖4-24 不同固相分率下，晶粒尺寸與停留時間的關係圖...................................103 圖4-25 不同預先攪拌時間下，視黏度與停留時間關係圖...................................104 圖4-26 晶粒結構發展示意圖..................................................................................105 圖4-27 短預先攪拌時間不同停留時間的SEM圖(a)10(b)40(c)90(min)..............106 圖4-28 長預先攪拌時間不同停留時間的SEM圖(a)10(b)40(c)90(min)..............107 圖4-29 不同預先攪拌時間下，晶粒尺寸與停留時間關係圖...............................108

    參考文獻
    [1] S.A. Metz, and M.C. Flemings, Hot Tearing in Cast Metals, AFS Transactions, Vol. 77, (1969), 329-334.
    [2] M.C. Flemings, Behavior of Metal Alloys in the Semisolid State, Metallurgical Transactions A, Vol. 22A, (1991), 957-981.
    [3] D.B. Spencer, R. Mehrabian, and M.C. Flemings, Rheological Behaviour of Sn-15 Pct Pb in the Crystallization Range, Metallurgical Transactions, Vol. 3, (1972), 1925-1932.
    [4] D. Ghosh, R. Fan, and C. VanSchilt, Thixotropic Properties of Semi-solid Magnesium Alloy AZ91D and AM50, The 3rd International Conference on Semi Solid Processing of Alloy and Composites, Tokyo, Japan, (1994), 85-94.
    [5] J.C. Gebelin, M Suery, and D. Favier, Characterization of the Rheological Behavior in the Semi-Solid State of Grain-Refined AZ91D Magnesium Alloys, Materials Science and Engineering A, Vol. 272 (1999), 134-144.
    [6] 蔡幸甫, 鎂合金Thixomolding®法的發展歷程, 工業材料, 第156期, (1999), 149-152.
    [7] C.J. Buynacek, and W.L. Winterbottom, High Volume Semi-Solid Forming of Aluminum Master Cylinders, Society of Automotive Engineers, (2000).
    [8] A.M. Mullis, Particle Dynamic Simulation of Semi-Solid Metal Rheology, The 7th International Conference on Semi-Solid Processing of Alloys and Composites, Tsukuba, Japan, (2002), 411-416.
    [9] C. Rouff, V. Favier, R. Bigot, M. Berveiller, and M. Robelet, Micro-Macro Modeling of the Isothermal Steady-State Semi-Solid Behavior, The 7th International Conference on Semi-Solid Processing of Alloys and Composites, Tsukuba, Japan, (2002), 423-427.
    [10] 陳惠釗, 黏度量測, 中國計量出版社, 北京, (1994).
    [11] H.A. Barnes, J.F. Hutton, and K. Walters, An Introduction to Rheology, Eleservier, (1989).
    [12] A.R.A. McLelland, N.G. Henderson, H.V. Atkinson, and D.H. Kirkwood, The Evaluation of Rheological Measurements on Semi-Solid Metal Slurries, The 2nd International Conference on the Semi-Solid Processing of Alloys and Composites, Cambridge, Massachusetts, USA, (1992), 290-295.
    [13] S.I. Bakhtiyarov, and R.A. Overfelt, Measurement of Liquid Metal Viscosity by Rotational Technique, Acta Materialia, Vol. 47, (1999), 4311-4319.
    [14] P.A. Joly, and R. Mehrabian, The Rheology of a Partially Solid Alloy, Journal of Materials Science, Vol. 11, (1976), 1393-1418.
    [15] A. Vogel, R.D. Doherty, and B. Cantor, Stir Cast Microstructure and Slow Crack Growth, Solidification and Casting of Metals, The Metals Society, London, (1979), 518-525.
    [16] L.S. Turng, and K.K. Wang, Rheological Behavior and Modeling of Semi-Solid Sn-15%Pn Alloy, Journal of Materials Science, Vol. 26, (1991), 2173-2183.
    [17] A. Tissier, D. Apelian, and G. Regazzoni, Magnesium Rheocasting: a Study of Processing-Microstructure Interaction, Journal of Materials Science, Vol. 25, (1990), 1184-1196.
    [18] R. E. Reed-Hill, and R. Abbaschian, Physical Metallurgy Principles, International Thomson Publishing, (1991).
    [19] B. R. Munson, D. F. Young, and T. H. Okiishi, Fundamentals of Fluid Mechanics, John Wiley & Sons, Inc., (1998).
    [20] H. Takuda, H. Fujimoto, and N. Hatta, Modelling on Flow Stress of Mg-Al-Zn Alloys at Elevated Temperatures, Journal of Materials Processing Technology, Vol. 80-81, (1998), 513-516.
    [21] H. Takuda, T. Yoshii, and N. Hatta, Finite-Element Analysis of the Formability of a Magnesium-Based Alloy AZ31 Sheet, Journal of Materials Processing Technology, Vol. 89-90, (1999), 135-140.
    [22] 馬寧元, 鎂壓鑄業的新發展趨勢, 鑄造月刊, 第123期, (1999), 15-18.
    [23] 郭永聖, 鎂合金之鑄造實務, 鑄工, 第57期, (1988), 50-59.
    [24] 經濟部工業局八十八年度工業技術人才培訓計畫講義, 金屬工業研究發展中心, (1999).
    [25] 賴耿陽, 工業材料之應用, 復漢出版社, 新竹, (1990), 35-38.
    [26] 賴耿陽, 非鐵金屬材料, 復漢出版社, 新竹, (1998), 174-191.
    [27] ASM, Magnesium Alloys, Metals Handbook 9th Edition, Vol. 6, (1985), 425-434.
    [28] O. Lunder, Effect of Mn Additions on the Corrosion Behavior of Mould-Cast Magnesium ASTM AZ91, Corrosion, Vol. 43, (1987), 291-295.
    [29] ASM, Magnesium Alloys, Metals Handbook 8th Edition, Vol. 8, (1976), 314-319.
    [30] 張永耀, 金屬熔銲學, 徐氏基金會, 台北, 下冊, (1976), 134-170.
    [31] S. Oka, Principles of Rheometry, Academic Press, (1960).
    [32] I.M. Krieger, and S.H. Maron, Direct Determination of the Flow Curves of Non-Newtonian Fluids. III. Standardized Treatment of Viscometric Data, Journal of Applied Physics, Vol. 25, (1954), 72-75.
    [33] C.C. Mao, J.C. Chen, H. Peng and M.L. Chang, Steady-state Rheological Behavior of Semi-Solid AZ91D Magnesium Alloy, Journal of the Chinese Society of Mechanical Engineers, Vol. 24, (2003), 385-389.
    [34] H. Peng, Material characterization and process development for the net-shape injection molding of semi-solid materials, Ph.D. Thesis, Cornell University, New York, USA, (1995).
    [35] ASM, Magnesium Alloys, Metals Handbook 8th Edition, Vol. 8, (1976), 134-137.
    [36] Y.S. Yang, and C.-Y.A. Tsao, Viscosity and Structure Variations of Al–Si Alloy in the Semi-Solid State, Journal of Material Science, Vol. 32, (1997), 2087-2092.
    [37] C.D. Yim, and K.S. Shin, Changes in Microstructure and Hardness of Rheocast AZ91HP Magnesium Alloy with Stirring Conditions, Materials Science and Engineering A, Vol. 395, (2005), 226-232.
    [38] G. Wan, and P.R. Sahm, Ostwald Ripening in the Isothermal Rheocasting Process, Acta Metallurgica et Materialia, Vol. 38, (1990), 967-972.
    [39] G. Wan, and P.R. Sahm, Particle Growth by Coalescence and Ostwald Ripening in Rheocasting of Pb-Sn, Acta Metallurgica et Materialia, Vol. 38, (1990), 2367-2372.
    [40] K. Sukumaran, B.C. Pai, and M. Chakraborty, The Effect of Isothermal Mechanical Stirring on an Al–Si Alloy in the Semisolid Condition, Materials Science and Engineering A, Vol. 369, (2004), 275-283.
    [41] S. Ji, K. Roberts, and Z. Fan, Isothermal Coarsening of Fine and Spherical Particles in Semisolid Slurry of Mg-9Al-1Zn Alloy under Low Shear, Scripta Materialia, Vol. 55, (2006), 971-974.
    [42] J.F. Seconde, and M. Suery, Effect of Solidification Condition on Deformation Behaviour of Semi-Solid Sn-Pb Alloys, Journal of Materials Science, Vol. 19, (1984), 3995-4006.
    [43] S. Annavarapu, and R.D. Doherty, Inhibited Coarsening of Solid-Liquid Microstructures in Spray Casting at High Volume Fractions of Solid, Acta Metallurgica et Materialia, Vol. 43, (1995), 3207-3230.
    [44] Z. Fan, Semisolid Metal Processing, International Materials Reviews, Vol. 47, (2002), 49-85.
    [45] L. Salvo, M. Suery, Y.D. Charentenay, and W. Loue, Microstructural Evolution and Rheological Behaviour in the Semi-Solid State of a New Al-Si Based Alloy, The 4th International Conference on the Semi-Solid Processing of Alloys and Composites, Sheffield, UK, (1996), 10-15.
    [46] M. Braccini, L. Salvo, M.Suery, and Y. Brechet, Influence of Thermal Treatments on Partial Remelting of Al-Cu Alloy, The 5th International Conference on the Semi-Solid Processing of Alloys and Composites, Golden, Colorado, USA, (1998), 371-378.
    [47] W.R. Loue, and M. Suery, Microstructural Evolution during Partial Remelting of Al-Si7Mg Alloys, Materials Science and Engineering A, Vol. 203, (1995), 1-13.
    [48] I. Seyhan, L. Ratke, W. Bender, and P.W. Voorhees, Ostwald Ripening of Solid-Liquid Pb-Sn Dispersions, Metallurgical and Materials Transactions A, Vol. 27, (1996), 2470-2478.
    [49] E.J. Zoqui, and M.H. Robert, Contribution to the Study of Mechanisms Involved in the Formation of Rheocast Structure, Journal of Materials Processing Technology, Vol. 109, (2001), 215-219.
    [50] D.B. Spencer, Rheology of liquid-solid mixtures of lead-tin, Ph.D. Thesis, Massachusetts Institute of Technology, Massachusetts, USA, (1971).

    QR CODE
    :::