實驗利用不同的製程參數，改變超細晶AA3003鋁錳合金的微結構，以及合金元素的固溶/析出量，並討論其影響。實驗利用ECAE施以大量的應變量，使AA3003鋁合金的晶粒細化。
隨著ECAE的應變量增加，晶粒逐漸的被細化成更小的次晶粒，AA3003的拉伸強度以及加工硬化率也都有明顯的提升。在ECAE擠製前，降低均質化溫度，則使材料有較多的二次相顆粒殘留，並且提升擠製後的拉伸強度，以及加工硬化率。而擠製後的材料，隨著後續退火溫度及時間的提升，微結構逐漸改變，且次晶粒逐漸長大，使得材料的強度也隨之下降，並且產生四種不同的拉伸變形行為。此外，在超細晶AA3003的退火行為中，有退火硬化的現象發生，其硬化程度又以高溫均質化的材料較為明顯。 超細晶AA3003鋁合金的應變速率敏感值(m)，受到ECAE的加工應變量不同，以及均質化溫度所影響。當ECAE加工應變量增加時，m也隨之提升，但m值仍小於低溫均質化處理後的材料。

表目錄 ....................................................................................................... iv
圖目錄 ......................................................................................................... v
一、前言 ..................................................................................................... 1
二、文獻回顧 ............................................................................................ 2
2-1 AA3003鋁合金............................................................................ 2
2-1-1 AA 3003鋁合金的析出物 ............................................... 3
2-2 等徑轉角擠型(equal channel angular extrusion, ECAE) ...... 5
2-2-1 等徑轉角擠型之原理 ...................................................... 5
2-2-2 ECAE的應變量............................................................... 6
2-3 超細晶金屬之機械性質 ............................................................. 7
2-3-1 超細晶金屬的強度 .......................................................... 8
2-3-2 超細晶的降伏下降(yield drop)現象 ............................. 9
2-3-3 超細晶金屬的延展性 .................................................... 10
2-3-4 超性晶材料的應變速率敏感度 ................................... 13
2-3-5 超細晶金屬的晶界特性 ................................................ 15
2-4 添加固溶合金元素的影響 ....................................................... 17
三、研究目的 .......................................................................................... 19
四、實驗方法 .......................................................................................... 20
4-1 實驗材料 ................................................................................... 21
4-2 均質化處理 (homogenization) ............................................... 21
4-3 等徑轉角擠型 (ECAE) ........................................................... 22
4-4 退火處理 (annealing) .............................................................. 22
4-5 微硬度測詴 (microhardness test) .......................................... 23
4-6 拉伸測詴 (tensile test) ............................................................ 24
4-7 微結構分析 (microstructure analysis) .................................. 25
五、實驗結果 .......................................................................................... 26
5-1 ECAE擠製後的微結構 ............................................................ 27
5-2 ECAE擠製AA3003 鋁合金的退火行為 ............................... 29
5-2-1 退火軟化曲線 ................................................................ 29
5-2-2 退火溫度造成的微結構變化 ....................................... 30
5-2-3 退火時間造成的微結構變化 ....................................... 31
5-3 超細晶AA3003鋁合金的拉伸變形行為 ............................... 32
5-3-1 ECAE擠製後的拉伸機械性質 .................................... 32
5-3-2 退火處理後的拉伸機械性質 ....................................... 34
5-3-3 低應變速率下的拉伸變形行為 ................................... 37
5-3-4 應變速率改變(strain rate jump)測詴 ......................... 38
5-3-5 拉伸後的表面變形與微結構 ....................................... 39
5-4 實驗結果總論 ........................................................................... 41
六、討論 ................................................................................................... 43
6-1 晶粒尺寸與降伏強度之關係 ................................................... 43
6-2 超細晶的降伏下降現象 ........................................................... 45
6-3 ECAE應變量對於超細晶AA3003的拉伸強度影響 ............ 47
6-4 均質化處理溫度對於超細晶AA3003的拉伸強度影響 ....... 48
6-5 超細晶AA3003的退火硬化現象 ........................................... 49
6-6 超細晶AA3003的應變速率敏感度 ....................................... 51
七、結論 ................................................................................................... 55
參考文獻 ................................................................................................... 57

[1] A.K. Vasudevan, R.D. Doherty, “Aluminum alloys – contemporary research and applications”, Academic press, (1989).
[2] 陳俊豪，「部分退火冷軋鋁合金之拉伸研究」，中山大學碩士論文，(2007)。
[3] Y.J. Li, L.Arnberg, “Evolution of eutectic intermetallic particles in DC-cast AA3003 alloy during heating and homogenization”, Mater. Sci. Eng. A, 347, (2003), 130.
[4] S.P. Chen, N.C.W. Kuijpers, S.V.D. Zwaag, “Effect of micro- segregation and dislocations on the nucleation kinetics of precipitation in AA3003”, Mater. Sci. Eng. A, 341, (2003), 296.
[5] A.L. Dons, Trondheim, Yanjun Li, Sunndalsφra, S. Benum, Mosjφen, C. marioara, Trondheim, A. Johansen, A. Håkonsen, Ch.J. Simensen, Oslo, E.K. Jensen,Kristiansand, “Homogenisation of AA3103 and AA3003 Part II: Heating”, Alumium, 81, (2005), 1150.
[6] V.M. Segal, “Materials processing by simple shear”, Mater. Sci. Eng. A, 197, (1995), 157.
[7] K. Nakashima, Z. Horita, M. Nemoto, T. G. Langdon, “Influence of channel angle on the development of ultrafine grains in equal-channel angular pressing”, Acta Mater., 46, (1998), 1589.
[8] V.M. Segal, K.T. Hartwig, R.E. Goforth, “In situ composites processed by simple shear”, Mat. Sci. Eng., A224, (1997), 107.
[9] Y. Iwahashi, J. Wang, Z. Horita, M. Nemoto, T.G. Langdon, “Principle of equal-channel angular pressing for the processing of ultra-fine grained materials”, Scripta Mater., 35, (1996), 143.
[10] M. Furukawa, Z. Horita, T.G. Langdon, “Factors influencing the shearing
61
patterns in equal-channel angular pressing”, Mater. Sci. Eng. A, 332, (2002), 97.
[11] S. Ferrasse, V.M. Segal, K.T. Hartwig, R.E. Goforth, “Microstructure and Properties of Copper and Aluminum Alloy 3003 Heavily Worked by Equal Channel Angular Extrusion”, Metal. Trans. A, 28A (1997) 1047.
[12] N. Tsuji, Y, Ito, Y Saito, Y Minamino, “Strength and ductility of ultrafine grained aluminum and iron produced by ARB and annealing”, Scripta Mater., 47 (2002) 893.
[13] C.Y. Yu, P.W. Kao, C.P. Chang, “Transition of tensile deformation behaviors in ultrafine-grained aluminum”, Actr Mater., 53 (2005) 4019. [14] M.A. Meyers, K.K. Chawla, “Mechanical behavior of materials”, (1996) 270.
[15] J.W. Wyrzykowski, M.W. Grabski, “Lueders deformation in ultrafine- grained pure aluminium”, Mater. Sci. Eng., 56 (1982) 197.
[16] N. Tsuji, Y, Ito, Y Saito, Y Minamino, “Strength and ductility of ultrafine grained aluminum and iron produced by ARB and annealing”, Scripta Mater., 47 (2002) 893.
[17] R.E. Reed-Hill, “Physical metallurgy principles”, 3rd (1992) 286.
[18] I. Sabirov, Y. Estrin, M.R. Barnett, I. Timokhina, P.D. Hodgson, “Enhanced tensile ductility of an ultra-fine-grained aluminum alloy”, Scripta Mater., 58 (2008) 163.
[19] I. Sabirov, Y. Estrin, M.R. Barnett, I. Timokhina, P.D. Hodgson, “Tensile deformation of an ultrafine-grained aluminium alloy: Micro shear banding and grain boundary sliding”, Acta Mater., 56 (2008) 2223.
[20] Y.M. Wang, E. Ma, “Three strategies to achieve uniform tensile deformationin a nanostructured metal”, Acta Mater., 52 (2004) 1699
[21] G.E. Dieter, “Mechanical metallurgy”, SI Metric edition, (1988), 290.
62
[22] Y.J. Li, X.H. Zeng, W Blum, “Transition from strengthening to softening by grain boundaries in ultrafine-grained Cu”, Acta Mater., 52 (2004) 5009.
[23] Y.M. Wang, E. Ma, “Three strategies to achieve uniform tensile deformationin a nanostructured metal”, Acta Mater., 52 (2004) 1699.
[24] G.J. Fan, H. Choo, P.K. Liaw, E.J. Lavernia, “Plastic deformation and fracture of ultrafine-grained Al–Mg alloys with a bimodal grain size distribution”, Acta Mater., 54 (2006) 1759.
[25] H. W. Höppel, J. May, M Goken, “Enhanced strength and ductility in ultrafine-grained aluminum produced by accumulative roll bonding”, Adv. Eng. Mater., 9 (2004) 781.
[26] H.W. Kim, S.B. Kang, N. Tsuji, Y. Minamino, “Elongation increase in ultra-fine grained Al–Fe–Si alloy sheets”, Acta Mater., 53, (2005), 1737.
[27] M.A. Meyers, K.K. Chawla, “Mechanical behavior of materials”, (1996),122-127.
[28] G.E. Dieter, “Mechanical metallurgy”, SI Metric edition, (1988), 307-308.
[29]P.L. Sun, C.Y. Yu, P.W. Kao, C.P. Chang, “Influence of boundary characters on the tensile behavior of sub-micron-grained aluminum”, Scripta Mater., 52, (2005), 265.
[30] Y.H. Zhao, J.F. Bingert, Y.T. Zhu, X.Z. Liao, R.Z. Valiev, Z. Horita, T.G. Langdon, Y.Z. Zhou, E.J. Lavernia, “Tougher ultrafine grain Cu via high-angle grain boundaries and low dislocation density”, App. Phy. Let., 92, (2008), 081903
[31] G.E. Dieter, “Mechanical metallurgy”, SI Metric edition, (1988), 203-205.
[32] Ø. Ryen, O. Nijs, E. Sjölander, B. Holmedal, H-E. Ekström, E. Nes, “Strengthening mechanisms in solid solution aluminum alloys”, Metal. Mater.Trans. A, 37A (2006) 1999.
[33] H.P. Stüwe, P. Les, “Strain rate sensitivity of flow stress, at large strain”, Acta Mater.,46,(1998),6375-6380.
[34] 庾忠義，「超細晶鋁之機械性質」，中山大學材料科學研究所博士論文，(2003)。
[35] D. Hull, D.J. Bacon, “Introduction to dislocation”, 4th (2001) 59.
[36] G.E. Dieter, “Mechanical metallurgy”, SI Metric edition, (1988), 197-201.
[37] 洪佩菁，「次微米晶粒鋁之拉伸變形行為」，中山大學碩士論文，(2004)。
[38] Y. Birol, “Recrystallization of a supersaturated Al-Mn alloy”, Scripta Mater., 59, (2008), 611. [39] Y. Birol, “Impact of homogenization on recrystallization of a supersaturated Al-Mn alloy”, Scripta Mater., 60, (2009), 5.
[40] Q. Wei, S. Cheng, K.T. Ramesh, E. Ma, “Effect of nanocrystalline and ultrafine grain sizes on the strain rate sensitivity and activation volume: fcc versus bcc metals”, Mater. Sci. Eng. A 381 (2004) 71–79 [41] Y.M. Wang, A.V. Hamza, E. Ma, “Temperature-dependent strain rate sensitivity and activation volume of nanocrystalline Ni”, Acta Mater., 54 (2006) 2715–2726
[42] M. Aghaie-Khafri, R. Mahmudi, “Flow Localization and Plastic Instability during the Tensile Deformation of Al Alloy Sheet”, Aluminum Res. Sum, (1998) 50-52.