本文研究主要是利用霍普金森高速撞擊試驗機，並配合加熱裝置，來探討Ti-15Mo-5Zr-3Al合金於高溫高速撞擊下之塑性變形行為。實驗條件為測試溫度從25℃到900℃、應變速率為8×102 s-1到8×103 s-1，再將實驗所得到數據及微觀觀察結果(OM、SEM、TEM)做分析，用來釐清應變速率及溫度對動態機械特性及其對應之微觀組織變化之影響，最後引用一合適材料構成方程式，描述Ti-15Mo-5Zr-3Al合金之高溫高速塑變行為，以作為工程模擬與分析之用。
實驗結果之數據分析指出，Ti-15Mo-5Zr-3Al合金機械性質受應變速率、溫度及應變量之影響甚鉅，在相同溫度條件下，其塑流應力值會隨應變速率之增加而上升；在相同應變速率條件下，其塑流應力值會隨溫度之增加而下降，而應變速率敏感性係數則隨應變速率區間之增加而增加，隨溫度之增加而減少；熱活化體積則與應變速率敏感性係數有相反趨勢。另外，在加工硬化係數方面：因Ti-15Mo-5Zr-3Al合金在變形過程中有會有應力軟化現象發生，故將其區分為硬化與軟化兩個區域討論(亦即軟化前後)。軟化前：在同一個應變速率條件之下，加工硬化係數會隨著溫度之升高而下降。而軟化後：在同一個應變速率下，加工硬化係數在材料相變態之前(溫度小於785℃)亦隨溫度之升高而下降，但相變態發生後(溫度小於785℃)，加工硬化係數隨即上升。其中，在整個變形過程中，包括相變態前後，加工硬化係數皆應變速率增加而增加。最後，藉由 Combine Johnson-Cook and Zerilli-Armstrong模式之構成方程式，另外加入理論溫升量修正，即可用來描述Ti-15Mo-5Zr-3Al合金於高溫高速撞擊下之塑變行為。
由破壞形貌觀察，得知材料受高速衝擊時，會有絕熱剪切帶產生，且隨溫度上升，其剪切帶寬度有變小之趨勢，另外，亦可發現剪切帶裡會有微空孔出現，藉由空孔聚集連結成裂縫，最後造成材料破壞之發生；在破斷面上觀察，發現其主要以延性破壞特徵之韌窩組織形貌分佈，故屬於延性破壞，且韌窩形貌會隨著應變速率及溫度之不同而有變化，由SEM觀察結果發現：隨應變速率愈高，整體韌窩形貌較密較深；隨溫度升高，在700℃以前(含700℃)，整體韌窩形貌較疏較淺，700℃以後(900℃)，整體韌窩形貌較密較深。從TEM之觀察分析，在相同溫度的條件時，隨著應變速率之增加，其差排數量增加、差排胞壁厚變厚。在相同應變速率條件時，隨著溫度上升，其差排胞之尺寸會隨著增加，而差排密度則會隨著減少；另外可觀察到長條平板狀α相(plate-like)數量隨著應變速率之增加並無明顯變化，隨著溫度上升則有變少之趨勢，且在溫度900℃則幾乎沒有。

A split-Hopkinson bar is used to investigate the plastic deformation behaviour of Ti-15Mo-5Zr-3Al alloy subjected to high temperature and high strain rate loading conditions. The mechanical testing is performed under strain rate ranging from 800 s-1 to 8000 s-1 and at constant temperature in range of 25 ℃ to 900 ℃. The OM, SEM and TEM techniques are used to analyze the fracture and microstructure characteristics of deformed specimens. Based on the macroscopic and microscopic results, the correlations between mechanical properties and microstructure were established.
The experimental results indicate that temperature, strain rate and strain influence material mechanical properties. At constant temperature, flow stress and strain rate sensitivity increase with increasing strain rate, but activation volume and work hardening coefficient decrease. Under constant strain rate, flow stress and strain rate sensitivity decrease with increasing temperature, but activation volume and temperature sensitivity increase. Due to the occurrence of softening effect phenomenon, work hardening coefficient is discussed separated before and after thermal instability. Work hardening coefficient decreases with increasing temperature under constant strain rate before the occurrence of thermal instability. After thermal instability occurs, work hardening coefficient also decreases with increasing temperature before the presence of phase transformation (i.e. 785 ℃), but increases after the presence of phase transformation. The fractography analysis indicate that fracture occurs after shear band formation, and that the width of shear band decreases with increasing temperature before phase transformation, but increases after phase transformation. It’s also found that both dimple and cleavage features appear on fracture surfaces. Observations of splats and incipient melt features or knobbles for specimen deformed at 700 ℃ and 8×103 s-1 prove that melting is occurred during deformation. Microstructural observations show that deformed substructure consists of dislocation and α phase. Dislocation density increases with increasing strain rate, but decrease with increasing temperature. The increase of dislocation density yields an augmentation of flow stress. The amount of α phase increase with increasing temperature before phase transformation, but dissolve after phase transformation. The Combine Johnson-Cook and Zerilli-Armstrong constitutive equation with the experimentally determined specific material parameters successfully describes the flow behaviour of the Ti-15Mo-5Zr-3Al alloy for the tested conditions.

1.H. Kolsky, "An Investigation of the Mechanical Properties of Materials at Very High Rates of Loading," Proceedings of the Physical Society, Vol. 62, pp. 676-699, 1949.

2.B. M. Butcher and C. H. Karnes, "Strain Rate Effects in Metals," J. Appl. Phys., Vol. 37, pp. 402-411, 1964.

3.F. E. Hauser, "Techniques for Measuring Stress-Strain Relations at High Strain Rates," Exp. Mech., Vol. 6, pp. 395-402, 1966.

4.Y. Leroy and M. Ortiz, In Mechanical Properties of Materials at High Rates of Strain, (ed. J. Harding), pp. 257-265, 1989.

5.D. J. Steinberg, S. G. Cochran and N. W. Guinan, "A Constitutive Model for Metals Applicable at High Strain Rate," J. Appl. Phys., Vol. 51, No. 3, pp. 1498-1504, 1980.
6.H. M. Kim, H. Takadama, T. Kokubo, S. Nishiguchi, T. Nakamura, "Formation of a bioactive graded surface structure on Ti-15Mo-5Zr-3Al alloy by chemical treatment," Biomaterials, 21, pp. 353-358, 2000.

7.Y. Okazaki, Y. Ito, K. Kyo and T. Tateishi, "Corrosion Resistance and Corrosion Fatigue Strength of New Titanium Alloys for Medical Implants without V and Al," Mater. Sci. Eng. A, Vol. 213, pp. 138-147, 1996.

8.Y. Okazaki, "Effect of Friction on Anodic Polarization Properties of Metallic Biomaterials," Biomaterials, No.23, pp. 2071-2077, 2002.

9.K. Tokaji, H. Shiota, J. C. Bian, "Fatigue crack propagation in β Ti-15Mo-5Zr-3Al alloy," Mater. Sci. Eng. A, Vol. 243, pp. 155-162, 1998.

10.K. Tokaji, J. C. Bian, T. Ogawa, M. Nakajima, "The microstructure dependence of fatigue behaviour in Ti-15Mo-5Zr-3Al alloy," Mater. Sci. Eng. A, Vol. 213, pp. 86-92, 1996.

11.P. Ludwik and Z. Vereins deut. Ing., 71, pp. 1532-1538, 1927.

12.G. R. Johnson, W. H. Cook, in: Proc. 7th Intern. Symp. on Ballistics, The Hague, Netherlands, pp. 541-547, 1983.

13.F. J. Zerilli and R. W. Armstrong, "Dislocation-Mechanics-Based Constitutive Relations for Material Dynamics Calculations," J. Appl. Phys., Vol. 61, pp. 1816-1825, 1987.

14.W. S. Lee and C. F. Lin, "Plastic Deformation and Fracture Behaviour of Ti-6Al-4V Alloy Loaded with High Strain Rate under Various Temperatures," Mater. Sci. Eng. A, Vol. 241, pp. 48-59. 1998.

15.W. S. Lee, G. L. Xiea and C. F. Lin, "The Strain Rate and Temperature Dependence of the Dynamic Impact Response of Tungsten Composite," Mater. Sci. Eng. A, Vol. 256, pp. 256-267, 1998.

16.M. S. J. Hashmi, A. M. S. Hamouda, "Development of a One-Dimensional Constitutive Equation for Metals Subjected to High Strain Rat and Large Strain," J. Strain Anal. Eng. Des., Vol. 29, pp. 117-127, 1994.

17.H. Zhao and G. Gray, "An Experimental Investigation of Compressive Failure Strength of Fibre-Reinforced Polymer-Matrix Composite Plates under Impact Loading," Mater. Sci. Eng. A, Vol. 207, pp. 46-50, 1996.

18.J. P. Joule, Phil. Trans. Royal Soc., London, Vol. 149, pp. 91-131, 1859.

19.J. Duffy, Y. C. Chi, "On the Measurement of Local Strain and Temperature during the Formation of Adiabatic Shear Bands," Mater. Sci. Eng. A, Vol. 157, pp. 195-210, 1992.

20.S. C. Liao, J. Duffy, "Adiabatic Shear Bands in A Ti-6Al-4V Titanium Alloy," J. Mech. Phys. Solids, Vol. 46, No. 11 pp. 2201-2231, 1998.

21.K. A. Hartley, J. Duffy and R. H. Hawley, "Measurement of the Temperature Profile during Shear Band Formation in Steels Deforming at High Strain Rates," J. Mech. Phys. Solids, Vol. 35, No. 3, pp. 283-301, 1987.

22.Marchand, J. Duffy, "An Experimental Study of the Formation Process of Adiabatic Shear Bands in a Structural Steel," J. Mech. Phys. Solids, Vol. 36, No. 3, pp. 251-283, 1988.

23.Y. B. XU, Y. L. Bai, Q. Xue and L. T. Shen, "Formation, Microstructure and Development of the Localized Shear Deformation in Low-carbon Steels," Acta mater. Vol. 44, No. 5, pp. 1917-1926, 1996.

24.R. Boyer, G. Welsch, E. W. Collings. "Materials Properties Handbook: Titanium Alloys, " Materials Park, OH ; ASM International, 1994.

25.Robinson, O. P., Ancient Rome：City Planning and Administration, London, New York, 1992.

26.Bobyn, J. D., Mortimer, E. S., Glassman, A. H., Engh, C. A., Miller, J., and Brooks, C., "Producing and Avoiding Stress Shielding: Laboratory and Clinical Observation of Noncemented Total Hip Arthroplasty," Clin. Orthop. Relat. Res., Vol. 274, pp. 79-96, 1992.

27.Steinemann, S. G., "Corrosion of Surgical Implants-in Vivo and Vitro Tests," Evaluation of Biomaterials, Wiley, New York, 1980.

28.Chen, A., Sridharan, K., Conrad, J .R., Fetherston, R. P., "Surface Modification of Ti-6Al-4V Surgical Alloy by Plasma Source Ion Implantation," Surf. Coat. Tech., Vol. 50, pp. 1-4, 1991.

29.Park, J. B., Biomaterials Science and Engineering, Plenum Press, New York, 1984.

30.Caceres, C. A., Medical Devices：Measurements, Quality Assurance, and Standards, ASTM, Philadelphia, 1983.

31.Bobyn, J. D., Glassman, A. H., Goto, H., Krygier, J., Miller, J., and Brooks, C., "The Effect of Stem Stiffness on Femoral Bone Resorption after Canine Porous-Coated Total Hip Arthroplasty," Clin. Orthop. Relat. Res., Vol. 261, pp. 196-213, 1990.

32.Dobbs, H. S., and Scales, J. T., "Behavior of Commercially Pure Titanium and Ti-318 (Ti-6Al-4V) in Orthopedic Implants," ASTM, Philadelphia, pp. 173-186, 1983.

33.Steinemann, S. G., "Titanium Alloys as Metallic Biomaterials," Ti Sci. Tech., Vol. 2, pp. 1327-1334, 1984.

34.Slanina, P., Frch, W., Bernhardson, A., Cedergreen, A., and Mattsson, P., "Influence of Dietary Factors on Aluminium Absorption and Retention in Brain and Bone of Rat," Acta Pharmocal. Toxicol., Vol. 56, pp. 331-336, 1985.

35.van der Voet, G. B., Marani, E., Tio, S., and de Wolff, F. A., "Aluminium Neurotoxicity," Histo and Cyto-Chemistry as a Tool in Environ. Toxicol. , Stuttgart, Germany, pp. 235-242, 1991.

36.Nichols, K. G., and Puleo, D. A., "Effect of Metal Ions on the Formation and Function of Osteoclastic Cells in Vivo," J. Biomed. Mater. Res., Vol. 35, pp .256-271, 1997.

37.Shettlemore, M. G., and Bundy, K. J., "Toxicity Measurement of Orthopedic Implant Alloy Degradation Products Using a Bioluminescent Bacterial Assay," J. Biomed. Mater. Res., Vol. 45, pp. 396-403, 1999.

38.Donachie M. J. Jr., Titanium: A Technical Guide, ASM, Ohio, 1989.

39.Tokaji, K., Bian, J. C., Ogawa, T., and Nakajima, M., "The Microstructure Dependence of Fatigue Behaviour in Ti-15Mo-5Zr-3Al Alloy," Mater. Sci. Eng. A, Vol. 213, pp. 86-92, 1996.

40.Ikeda M., Komatsu, S. Y., Sugimoto, T., and Hasegawa, M., "Effect of Two Phase Warm Rolling on Aging Behavior and Mechanical Properties of Ti-15Mo-5Zr-3Al Alloy," Mater. Sci. Eng. A, Vol. 243, pp. 140-145, (1998).

41.T. Nishimura, M. Nishigaki and Y. Moriguchi, "Characteristics of Beta Titanium Alloy Ti-15Mo-5Zr-3Al," 神戶製鋼技報, Vol. 32, No.1, pp. 52-55.

42.Shin-ya Komatsu, Masahiko Ikeda, Takashi Sugimoto, Kiyoshi Kamei, Oaamu Maesaki, Masa-aki Kojima, "Aging behaviour of Ti-15Mo-5Zr and Ti-15Mo-5Zr-3Al alloy up to 573K," Mater. Sci. Eng. A, 213, pp.61-65, 1996.

43.Masahiko Ikeda, Shin-ya Komatsu, Takashi Sugimoto, Makoto Hasegawa, "Effect of two phase warm rolling on aging behavior and mechanical properties of Ti-15Mo-5Zr-3Al alloy," Mater. Sci. Eng. A, 243, pp.140-145, 1998.

44.U. S. Lindholm and L. W. Yeakly, "High Strain Rate Tension and Compression, " Exp. Mech., Vol. 3, pp. 81-88, 1983.

45.M. A. Meyers, Elastic Waves, "Dynamics Behavior of Materials," Jhon Wiely & Son, pp. 23-65, 1994.

46.林奇鋒, "鈦合金(Ti-6Al-4V)之高速高溫變形行為分析, " 國立成功大學機械工程研究所碩士論文, pp. 5-23, 1996.

47.J. D. Campbell, "Dynamic Plasticity-Macrosopic and Microscopic Aspects," Mat. Sci. Eng., Vol. 12, pp. 3-21, 1973.

48.D. Klahn, A. K. Mukherjee and J. E. Dorn, Proceedings of the 2nd International Conference on the Strength of Metals and Alloys, Vol. III, ASM, pp. 951, 1970.

49.J. D. Campbell and W. G. Ferguson, "The Temperature and Strain-Rate Dependence of the Shear Strength of Mild Steel," Phil. Mag., Vol. 21, pp. 63-82, 1970.

50.A. Seeger, "Dislocation and Mechanical Properties of Crystals," Phil. Mag., Vol. 46, pp. 1194-1217, 1955.

51.U. S. Lindholm and L. M. Yeakly, "Dynamic Deformation of Single and Polycrystalline Aluminum," J. Mech. Phys. Solids, Vol. 13, pp. 41-49, 1965.

52.W. G. Ferguson, A. Kumar and J. E. Dorn, "Dislocation Damping in Aluminum at High Strain Rates," J. Appl. Phys., Vol. 38, No. 4, pp. 1863-1869, 1967.

53.J. D. Campbell and A. R. Dowling, "Behaviour of Materials Subjected to Dynamic Incremental Shear Loading," J. Mech. Phys. Solids, Vol. 18, pp. 43-63, 1970.

54.W. S. Lee, C. F. Lin, "Impact Properties and Microstructure Evolution of 304L Stainless-Steel," Mater. Sci. Eng. A, Vol. 308, pp. 124-135, 2001.

55.G. E. Dieter, Workability Testing Techniques, pp. 57-59, Metals Park, Oh: ASM, 1984.

56.J. C. Gelin, J. Oudin, and Y. Ravalard, "Determination of the Flow Stress-Strain Curve for Metals Form Axisymmeetric upsetting," J. of Mech. Work. Tech., Vol. 5, pp. 297-308, 1981.

57.R. Liang, A. S. Khan, "A Critical Review of Experimental Results and Constitutive Models for BCC and FCC Metals over a Wide Range of Strain Rates and Temperature" Int J Plasticity, Vol. 15, pp.963-980, 1999.

58.W. Johnson, Impact Strength of Material, Edward Arnold, pp. 134-135, 1972.

59.L. E. Malvern, J Appl. Mech., Vol.18, pp. 261-281, 1951.

60.J. D. Campbell, A. M. Eleiche, amd M. C. C. Tsao, "Fundamental Aspects of Structural Alloy Design," Plenum Publishing Corp. New York, pp. 545-563, 1977.

61.J. Duffy, Proc. Workshop on Shear Localization, Brown Univ. Report MRL-E-127, pp. 19-29, 1981.

62.H. Kobayashi and B. Dodd, "A Numerical Analysis for the Formation of Adiabatic Shear Bands Including Void Nucleation and Growth," Int. J. Impact Eng., Vol. 8, pp. 1-13, 1989.

63.F. J. Zerilli and R. W. Armstrong, "Dislocation-Mechanics-Based Constitutive Relations for Material Dynamics Calculations," J. Appl. Phys., Vol. 61, pp. 1816-1825, 1987.

64.F. J. Zerilli and R. W. Armstrong, "The Effect of Dislocation Drag on the Stress-Strain Behavior of F.C.C Metals," Acta metal. Mater., Vol. 40, No. 8, pp. 1803-1808, 1992.

65.F. J. Zerilli and R. W. Armstrong, "Constitutive Equation for HCP Meatls and High Strength Alloy Steels," High strain rate effects on polymer, Metal and Ceramic Matrix Composites and Other Advanced Materials, AD-Vol. 48, pp. 121-126, ASME 1995.

66.R. W. Klopp, R. J. Clifton and T. G. Shawki, "Pressure Shear Impact and Dynamic Viscoplastic Response of Metals," Mech. Mater., Vol. 4, pp. 375-385, 1985.

67.M. Zhou, A. Needleman and R. J. Clifton, "Finite Element Simulations of Shear Localization in Plate Impact," J. Mech. Phys. Solids, Vol. 42, pp. 423-458, 1994.

68.T. J. Holmquist and G. R. Johnson "Determination of Constants and Comparison of Results for Various Constitutive Models," J. Phys. Ⅲ, Vol. 1, pp. 853-860, 1991.

69.Sloter, L. E., and Piehler, H. R., "Corrosion Fatigue Performance of Stainless Steel Hip Nails-Jewett Type," ASTM, Philadelphia, pp. 173-192, (1979).

70.Y. Bai and B. Dodd: Adiabatic Shear Localization, Pergamon Press, Oxford, pp. 1-3, 1992.

71.R. D. Curran, L. Seaman and D. A. Shockey, "Linking Dynamic Fracture to Microstructural Process, Shock Wave and High-Strain-Rate Phenomena in Metal: Concepts and Applications, " pp. 22-26, 1980.

72.U. S. Lindholm, in Techniques in Metals Research, Vol. 5, Part1, R. F. Bunshah (ed.), Wiley-Interscience, New York, pp. 199, 1971.

73.G. E. Dieter, "Thermally Activated Deformation, Mechanical Metallurgy," pp. 310-315, 1988.

74.H. N. Azari, G. S. Murty and G. S. Upadhyana, "High Temperature Deformation of Rapidly Solidified 7091 Powder Metallrugy Aluminum Alloy," Mat. Sci. and Tech., Vol. 9, No. 8, pp. 686-690, 1993.

75.E. Bayraktar, S. Altintas, “Some Problems in Steel Sheet Forming Processes”, J. Mat. Process. Technol., Vol. 80-81, pp. 83-89, 1998.

76.Kei Ameyama, Kimihiko Yamashita, Teruhiko Inaba and Masaharu Tokizane, "Formation of (α+β) Microduplex Structure and Mechanical Properties in Meta-Stable β Titanium Alloys," J. Jpn. I. Met, Vol. 53, No. 11, pp. 1098-1104, 1989.

77.R. K. Ham, Phil. Mag., Vol. 6, pp. 1183, 1961.

78.Bennett, L. H., Murray Joanne L., Massalski, T. B., Binary alloy phase diagrams /editor-in-chief, Thaddeus B. Massalski ; editors, Joanne L. Murray, Lawrence H. Bennett, Hugh Baker., Metals Park, Ohio :American Society for Metals, 1986.

79.N. Nomura, T. Kohama, I.H. Oh, S. Hanada, A. Chiba, M. Kanehira, K. Sasaki, "Mechanical properties of porous Ti–15Mo–5Zr–3Al compacts prepared by powder sintering," Mater. Sci. Eng. C, Vol. 25, pp. 330-335, 2005.

80.C. R. Houska and V. Rao, "Determination of Volume Fraction in Multiphase Systems Using Incomplete Pole Figures," Metall. Mater. Trans. A, Vol. 9A, pp.1483-1485, 1978.

81.V. B. Rao and C. R. Houska, "Kinetics of the Phase Transformation in a Ti-15Mo-5Zr-3Al Alloy as Studied by X-Ray Diffraction," Metall. Mater. Trans. A, Vol. 10A, pp.355-358, 1979. 4864.

82.R. W. K. Honeycombe and H. K. D. H. Bhadeshia, Steels Microstructure and Properties 2nd Edition, Edward Arnold, pp. 55, 1995.

83.S. Kim and Y. Yoo, "Dynamic Recrystallization Behavior of 304 Stainless Steel," Mater. Sci. Eng. A, Vol. 311, pp. 108-113, 2001.

84.H. Guo, A. Yamamoto, M. Enomoto, "Inverse tent-sharped surface relief of α plates in a Ti-Mo alloy," Scripta Mater. 43, pp. 899-903, 2000.

85.A.G. Odeshi, S. Al-ameeri, M.N. Bassim, "Effect of high strain rate on plastic deformation of a low alloy steel subjected to ballistic impact," J. Mater. Process. Tech., 162-163, pp. 385-391, 2005.

86.Katsuhiko Machara, Kenji Doi, Tomiharu Matsushita and Yoshio Sasaki, "Application of Vanadium-Free Titanium Alloys to Artificial Hip Joints," Mater. Trans., Vol. 43, No. 12, pp. 2936-2942, 2002.

87.M. L. Lovato, and M. G. Stout, "Compression Testing Techniques to Determine the Stress/Strain Behaviour of Metals Subject to Finite Deformation," Metall. Trans. A., Vol. 23A, pp. 935-951, 1992.

88.U. S. Lindholm, in Techniques in Metals Research, Vol. 5, Part1, R. F. Bunshah (ed.), Wiley-Interscience, New York, pp. 199, 1971.

89.Li Qing, "New Type of Titanium Alloys for Man-Made Thigh Joint. " 上海鋼研, No. 1, pp. 16-21, 2002.

90.YU Si-rong, "The Research Present Status and Tendency of Biomedical Titanium Alloys," Mater. Sci. Eng., Vol. 18, No. 2, pp131-134, 2000.

91.Y. Bai and B. Dodd: Adiabatic Shear Localization, Pergamon Press, Oxford, pp. 1-3, 1992.

92.M. E. Backman, S. A. Schulz, J. C. Schulz and J. K. Pringle, "Scaling Rules for Adiabatic Shear," in Metallurgical Applications of Shock Wave and High-Strain-Rate Phenomena (eds. L. E. Murr, K. P. Staudhammer and M. A. Meyers) pp. 675-688, Marcel Dekker Inc., New York, 1986.

93.林奇鋒, "304L不銹鋼在未預變形及預變形條件下之高速撞擊特性與微觀組織的比較研究," 國立成功大學機械工程研究所博士論文, pp. 117-119, 2002

94.J. P. Hirth, G. Spanos, M. G. Hall, H. I. Aaronson, "Mechanismd for the development of tent-sharped and invariant-plane-strain-type surface reliefs for plates formed during diffusional phase trandformations," Acta. Mater. Vol. 46, No. 3, pp. 857-868, 1998.