本研究之目的主要是了解金屬玻璃微型柱於奈米壓縮實驗中所得到之臨界負載量並驗證其理論上柱的臨界負載值，且基於理論與實驗的驗證比較模擬分析於臨界負載值的誤差，並建構圓柱(截面為圓形)及錐柱(截面沿軸向變化)得其柱所能承受之最大負載值會使微型柱開始產生塑性變形行為，並再以模擬的方式建構不同之細長比(aspect ratio)於圓柱與錐柱歸納出微型柱在承受壓縮行為下達臨界負載值時會由剪切帶或挫曲還是直接達到降伏的何項因素導致金屬玻璃微型柱材料開始塑性變形。
實驗中將鋯基金屬玻璃(Zr-based MG)利用場發射雙束型聚焦離子切割儀(Dual-Beam Focused Ion Beam；DB-FIB)來製備成高度5.4 μm之柱狀材料，並用穿透式電子顯微鏡(Transmission Electron Microscope；TEM) 內載有奈米壓痕(Nano-indenter)，使其成為穿透式電子顯微鏡可同步觀察及執行奈米壓縮試驗(In-situ TEM)，量測到微型柱於底部長寬20 μm、厚度2 μm之臨界負載值大約在20.1 ~ 28.3 μN而理論上所計算為28 μN，經由模擬方式得到約18.5 μN。實驗與理論上之值相當接近，而模擬上的數值亦非常接近，所以額外定高度5 μm及Taper angle 3̊ 於模擬上將錐柱與圓柱分為細長比2、3、4、5、6、7、8建立模型並分析，其模擬結果與理論值比較，得到最大負載值於細長比4以上亦相當接近，也將壓頭以相同的速度模擬不同的細長比錐柱，在5以上時微型柱達臨界負載時會轉為挫曲並開始塑性變形，而4 ~ 5之間微型柱是因剪切帶主導轉為塑性變形其數值約落在1.05 GPa，在4以下則是微型柱受壓縮直接達到降伏值1.38 GPa。

The main purpose of this study is to understand the critical load bulk metallic glass micropillars in compression experiment, and verify the critical load with the column theory. The critical load based on theoretical and experiment values by simulation analysis is difference of the critical load values. We built the micropillars by simulation analysis and obtained the maximum loads, which damaged them with behavior of the plastic deformation. The micropillars are constructed by the different aspect ratios on the column of simulation, and then the aspect ratios are summarized under the micropillars on compression behavior of the load reaches the critical value. The load value increases to the critical load leading to the micropillar maybe be shear banding, buckling or yielding. We have to determine the phenomenon leading to failure of the bulk metallic glass micropillar.
The material Zr-based metallic glass is used dual-beam type field emission focused ion cutting instrucment(DB-FIB) to prepared by micropillar of length 5.4 μm in experiment. From In-situ TEM experiments to measure the micropillar about the value of the critical load 20.1 ~ 28.3 μN on based length 20 μm thickness 2 μm, while the theoretical calculations is 28 μN and the simulation to be about 18.5 μN .Experimental and theoretical value of consistency is quite high that was closed to critical load as compared with simulated values, additional height is 5um ,and the micropillars with and without 3̊ taper angle are differentiated into 7 groups by the aspect ratio 2、3、4、5、6、7、and 8. These groups are used to build the model and simulation data, and the result is compatible with theoretically critical load value in elastic region. When the investigation set the indenter velocity fixed, the simulation results show that the micropillar with aspect ratio above 5 are buckled; however, with the aspect ratio between 4 and 5 are damaged by shear bend, and the value is 1.05 GPa; with the aspect ratio below 4 can be compressed directly to yielding value about 1.38GPa.

[1]M.F. Ashby, A.L. Greer, “Metallic glasses as structural materials”, Scripta Material, 54 (2006) 321-326.
[2]M.F. Ashby, “Materials Selection in Mechanical Design”, Pergamon Oxford, Ch.6 (1992).
[3]A.L. Greer, A. Castellero, S.V. Madge, I.T. Walker, J.R. Wilde, “Nanoindentation studies of shear banding in fully amorphous and partially devitrified metallic allys”, Materials Science and Engineering, A 375–377 (2004) 1182–1185.
[4]Douglas C. Hofmann, Jin-Yoo Suh, Aaron Wiest, Gang Duan, Mary-Laura Lind, Marios D. Demetriou, William L. Johnson, “Designing metallic glass matrix composites with high toughness and tensile ductility”, nature letters, 451 (2008) 1085-1089
[5]A. Peker, W. L. Johnson, “A highly processable metallic glass:Zr41.2Ti13.8 Ni10.0Be22.5”, Appl. Phys. Lett., 63 (1993) 2342-2344.
[6]Z. Xue, Y. Huang, K.C. Hwang, M. Li, “The influence of indenter tip radius on the micro-indentation hardness”, Journal of Engineering Materials and Technology, 124 (2002) 371.
[7]A. C. Fischer-Cripps, Nanoindentation, Springer, NY (2004).
[8]S. Xie, E.P. George, “Hardness and shear band evolution in bulk metallic glasses after plastic deformation and annealing”, Acta Materialia, 56 (2008) 5202.
[9]P. Thamburaja, H. Pan, F.S. Chau, The evolution of microstructure during twinning: Constitutive equations, finite-element simulations and experimental verification”, International Journal of Plasticity, 25 (2009) 2141.
[10]X.L. Wu et.al, “Prevalence of shear banding in compression of Zr41Ti14Cu12.5Ni10Be22.5 pillars as small as 150 nm in diameter, Acta Materialia, 57 (2009) 3562–3571.
[11]T.C. Hufnagel et. al, “Deformation and failure of Zr57Ti5Cu20Ni8Al10 bulk metallic glass under quasi-static and dynamic compression”, J. Mater. Res., Vol. 17, 6 (2002) 1441-1445.
[12]T.G. Nieh, C. Schuh, J. Wadsworth et.al, “Strain rate-dependent deformation in bulk metallic glasses”, Intermetallics, 10 (2002) 1177–1182.
[13]Toshiji Mukai et. al, “Effect of strain rate on compressive behavior of a Pd40Ni40P20 bulk metallic glass”, Intermetallics, 10 (2002) 1071–1077.
[14]De Hosson et. al, “Effects of size on the mechanical response of metallic glasses investigated through in situ TEM bending and compression experiments”, Acta Materialia, 58 (2010) 189–200.
[15]J. Wright, “Shear band processes in bulk metallic glasses”, Doctoral dissertation at Stanford University Materials Science and Engineering, 2003.
[16]K M. Flores, “Structural changes and stress state effects during inhomogeneous flow of metallic glasses”, Scripta Materialia, 54 (2006) 327–332.
[17]C A. Schuh, A C. Lund, “Yield surface of a simulated metallic glass”, Acta Materialia, 51 (2003) 5399–5411.
[18]Argon A.S, “Plastic deformation in metallic glasses.”, Acta matell, 27 (1979) 47.
[19]Argon A.S, Shi L T., “Development of visc-plastic deformation in metallic glasses.”, Acta matell, 31 (1983) 499.
[20]Chen MW, “Mechanical behavior of metallic glasses: Microscopic understanding of strength and ductility.”, Annu. Rev. Mater. Res., 38 (2008) 445.
[21]Dongchan Jang et. al, “Effects of size on the strength and deformation mechanism in Zr-based metallic glasses”, International Journal of Plasticity, 2010.
[22]林坤楠, “材料力學”, 滄海, 台北,2003.
[23]R. C. Hibbeler, “Mechanics of materials”, Prentice Hall, Singapore, 2005.
[24]Johon O. Hallquis, “LS-DYNA theory manual”, LSTC, California, 680, 2006.
[25]虎門科技公司, “ANSYS/LS-DYNA教育訓練手冊”, 虎門科技, 台北, 2009.
[26]Saeed Moaveni, “Finite element analysis theory and application with ANSYS”, Prentice Hall, USA, 2003.
[27]郝好山, 胡仁喜, 康士廷, “ANSYS 12.0 LS-DYNA非線性有限元分析”,機械工業, 北京, 2010.
[28]LSTC, “LS-DYNA keyword user’s manual”, LSTC, California, 2007.
[29]Fusahito Yoshida, “Fundamentals of elastic plastic mechanics”, Wu-Nan Book Inc., Taiwan, 2007.
[30]D. Raabe, D. Ma, F. Roters, “Effects of initial orientation, sample geometry and friction on anisotropy and crystallographic orientation changes in single crystal microcompression deformation: A crystal plasticity finite element study”, Acta Materialia, 55 (2007) 4567–4583.
[31]K.T. Ramesh, H. Zhang, Q. Wei, B.E. Schuster, “The design of accurate micro-compression experiments”, Scripta Materialia, 54 (2006) 181–186.
[32]P.A. Shade et. al, “A combined experimental and simulation study to examine lateral constraint effects on microcompression of single-slip oriented single crystals”, Acta Materialia, 57 (2009) 4580–4587.
[33]陳冠維, “壓痕試驗於金屬玻璃中形成剪切帶之研究” ,國立成功大學機械工程學系博士論文, 2010.
[34]Eckert, J. et. al, “Structural bulk metallic glasses with different length-scale of constituent phases”, Intermetallics, 10 (2002) 1183–1190.
[35]白金烽, “LS-DYNA3D理論基礎與實例分析”, 科學, 北京, 2005.