本研究以ECAE製備AA1050極細晶商用純鋁•經ECAE後在250℃下退火一小時得到晶粒尺寸為0.59μm的極細晶鋁試片。在室溫下以應變速率7.1×10-4 s-1沿ECAE 模具之X、Y、Z方向壓縮進行壓縮試驗。沿X軸壓縮試驗除7.1×10-4 s-1之應變速率外，還有10-5 s-1應變速率之壓縮試驗。此外另以X軸壓縮試片於變形溫度100℃、150℃及175℃下進行5×10-5 s-1、7.1×10-4 s-1、10-1 s-1三種不同應變速率之壓縮試驗。經壓縮之試片以光學與掃描式電子顯微鏡觀察這些試片shear bands的生成情況與表面形貌，另外也以EBSD分析shear bands晶粒方位的變化。
　　研究發現，不同方向壓縮不會影響shear bands的生成。隨壓縮溫度的上升，shear bands的生成傾向隨之降低。隨著應變速率增快，shear bands的生成傾向也隨之增強，應變速率變慢則有相反之效果。此外shear bands的生成與表面波浪狀起伏的均勻變形區域兩種變形機制間互相相容。由EBSD分析得知，結晶方位會以垂直試片表面方向，Y方向，為旋轉軸旋轉一角度，並產生較強的texture。

In this study, ultrafine-grained commercial purity AA1050 aluminum was produced by equal channel angular extrusion (ECAE).Annealing at 250℃ was able to give a grain size of 0.59μm. Specimens were compressed along different ECAE axis under a strain rate of 7.1×10-4 s-1at room temperature. Compression tests were also performed under 5×10-5 s-1, 7.1×10-4 s-1 ,and 10-1 s-1 strain rates at 100℃,150℃ ,and 175℃. Surface morphology of specimens was observed by optical and scanning electron microscopes to study the generation of shear bands. Texture within shear bands was analyzed by electron backscattered diffraction (EBSD).

The present research found that, different compression direction has little effect on the generation of shear bands. Increasing compression temperature and decreasing strain rates have the effect of decreasing the degree of strain localization of shear bands. Shear band deformation is compatible with the uniform deformation occurred outside shear bands. Texture change within shear bands is rotated about an axis perpendicular to the specimen surface, and strengthens the texture component.

目錄 I
圖目錄 II
一、前言 1
二、文獻回顧 2
2-1 等徑轉角擠型（Equal Channel Angular Extrusion, ECAE） 2
2-1-1 等徑轉角擠製之原理 2
2-1-2 擠製路徑的影響 2
2-2 極細晶材料（ultrafine grained　material）的機械性質 3
2-2-1 極細晶材料的強度 3
2-2-2 極細晶材料的延展性 4
2-3 極細晶材料的應變集中行為 5
2-4 影響Shear Bands的生成與形貌的因素 8
三、研究目的 14
四、實驗方法 15
4-1 材料與ECAE製程 15
4-2 壓縮試驗 15
4-3 EBSD試片製作與量測 16
五、實驗結果與討論 18
5-1 不同壓縮軸Shear Bands的形貌 18
5-2 導入應變對室溫下Shear Bands的生成之影響 20
5-3 溫度對Shear Bands的生成的影響 21
5-4 應變速率對Shear Bands的生成的影響 23
5-5 EBSD分析Shear Bands晶粒方位之變化 26
六、結論 28
七、參考文獻 29
圖表 31

[1] Y. Iwahashi, J. Wang, Z. Horita, M. Nemoto, T.G. Langdon, Scripta Mater., 35 (1996) 143.
[2] P. L. Sun, P. W. Kao, C. P. Chang, Metall. Mater. Trans A.35 (2003) 1359.
[3] K. Nakashima, Z. Horita, M. Nemoto, T. G. Langdon, Acta Mater. 46 (1998) 1589.
[4] C.Y. Yu, P.W. Kao, C.P. Chang , Actr Mater. 53 (2005) 4019.
[5] J.E. Carsley, A. Fisher, W.W. Milligan , Metall. Mater. Trans. A 29A(1998) 2261.
[6] C.Y. Yu, P.L. Sun , P.W. Kao, C.P. Chang , Scripta Materialia. 52(2005) 359 .
[7] J.E. Carsley, W.W. Milligan, X.H. Zhu, and E.C. Aifantis , Scripta Materialia. 36(1997) 727.
[8] S. Cheng, J.A. Spencer, W.W. Milligan, Acta Mater. 51 (2003) 4505.
[9] D. Jia, K.T. Ramesh, E. Ma, Acta Mater. 51 (2003) 3495.
[10] Q. Wei, D. Jia, K. T. Ramesh, and E. Ma, Appl. Phys. Lett. 81(2002)1240.
[11] P.L. Sun, E.K. Cerreta, G.T. Gray and J.F. Bingert, Metall. Mater. Trans A 37 (2006) 2983.
[12]蕭郡逸,極細晶鎂合金之變形特性,碩士論文,國立中山大學材料與光電科學學系研究所(2009)
[13] Y.M. Wang, M. Chen, F. Zhou, E. Ma, Nature 419 (2002) 912.
[14] Y.M. Wang, E. Ma, Acta Mater 52(2004) 1699.
[15] Y.H. Zhao, X.Z. Liao, S. Cheng, E. Ma, Y.T. Zhu , Adv. Mater. 18 (2006) 2280.
[16] E. Ma, J Metal 58(4) (2006) 49.
[17] E. Ma, Scripta Mater 49(2003) 663.
[18] D. Jia, Y.M. Wang, K.T. Ramesh, E.Ma, Y.T.Zhu, R.Z. Valiev, Appl Phys Lett. 79 (2001) 611.
[19] R.Islamgaliev, N.Yunusova, I.Sabirov, A.Sergueeva, R.Valiev, Mater.Sci.Eng. A
319-321 (2001) 877
[20] R.Z. Valiev. Adv Eng Mater 5(2003) 296,
[21]黃聖傑,純鋁經等徑轉角擠型之機械性質異向性研究, 碩士論文,逢甲大學材料科學與工程學系(2010)
[22]周應文,壓縮方向對極細晶AZ31鎂合金變形行為的影響,碩士論文,國立中山大學材料與光電科學學系研究所(2010)
[23]李文讀,極細晶AZ31鎂合金之製造與變形行為研究, 博士論文,國立中山大學材料與光電科學學系研究所 (2010)

[24] W. T . Lee,Y.W Chou, C. I. Hsiao, C. P. Chang, L. Chang, P. W. Kao,
Metall. Mater. Trans A, 41(2010) 3282.
[25] W. T. Lee, S. X. Ding, D. K. Sun, C. I. Hsiao, C. P. Chang, L. Chang, P. W. Kao
Metall. Mater. Trans A, 42 (2011)2909.
[26] S.R. Agnew, D.W. Brown, and C.N. Tome, Acta Mater. 54(2006) 4841
[27] I. Sabirov, Y. Estrin, M.R. Barnett, I. Timokhina, P.D. Hodgsona, Scripta Mater.58 (2008) 163.
[28] I. Sabirov, Y. Estrin, M.R. Barnett, I. Timokhina, P.D. Hodgson, Acta Mater. 56(2008) 2223.
[29] G.J. Fan, G.Y. Wang, H. Choo, P.K. Liaw, Y.S. Park ,B.Q. Han, E.J. Lavenia,
Scripta Mater 52 (2005) 929.
[30] G.J. Fan, H. Choo, P.K. Liaw , E.J. Lavenia , Acta Mater. 54(2006) 1759