ZrCuAgAl非晶合金体系中的塑性变形能力研究
|
摘要
众所周知,大块非晶合金拥有良好的综合力学性能,比如高强度,高硬度,高的弹性极限等等,因此它们被认为是存在潜在应用前景的结构材料。在制备大尺寸的非晶合金上,人们已经取得了巨大的成功,在Zr基,Pd基,Y基,Mg基,La基等众多体系中都制备出了直径20mm以上的大块非晶合金。然而,这些新材料的最大缺点—缺乏塑性变形能力,严重的影响了这类材料作为结构材料的应用前景。众多的科研工作者在提高非晶合金塑性变形能力方面进行了大量的工作。据报道,非晶基体中引入一定量的晶化相形成的复合物可以展现出拉伸塑性,引入的第二相颗粒与基体之间的相互作用会有效的阻止剪切带的拓展。同样,很多研究表明,通过压缩,冷轧,热喷丸引入预变形同样可以提高非晶合金的变形能力。更有意思的是,一系列的单相非晶合金可以展现出良好的压缩塑性变形能力,这种良好变形能力的获得往往是基于(1)高的蒲松比；(2)化学成分或者微结构的不均匀性以及相分离；(3)变形诱导纳米晶的出现；(4)快速冷却或者微合金化引入大量的自由体积。所有这些猜想并没有被完全证实,但是它们仍然为提高单相非晶合金的塑性变形能力提供了非常有价值的线索。
最近,一系列直径20mm以上的ZrCuAgAl大块非晶合金被开发出来,这些合金非晶形成能力极强,仅仅通过电弧熔炼后的缓慢冷却,25克重的合金锭子就可以形成完全的非晶。但是这些非晶然后存在着塑性变形能力较差的致命问题,因此在该体系中开发出兼具良好的非晶形成能力以及出色的塑性变形能力的新型合金是非常有价值和意义的。在本项工作中,我们通过成分选择,在一百多个成分点中最终挖掘出了一个理想的合金,该合金可以很容易的通过铜模吸铸的方法制备出长10mm厚1mm的非晶合金,并且所制备的非晶合金表现出了良好的压缩塑性和弯曲塑性。为了进一步了解这种非晶合金,我们对其热学性能,力学性能以及原子结构进行了表征,并且从微观尺度和宏观尺度对该合金的塑性本质进行了探索。通过与Zr_(46)Cu_(37.6)Ag_(8.4)Al_8(形成能力最强成分)的对比,我们发现,新开发的Zr_(53.8)Cu_(31.6)Ag_(7.0)A_(l7.6)非晶合金由于含有Zr原子较多,从而使得径向分布函数中最近邻壳层中Zr-Zr原子对较多,这也使得径向分布函数第一峰右侧曲线较陡,从而使得变形过程中卷入变形的原子数量增多同时也增加了多条剪切带产生的可能性。该发现可能从结构角度对于非晶合金塑性变形能力的提高提供有效的指导。
Bulk metallic glasses (BMGs) combine superior mechanical properties such as high strength and large elastic strain with excellent glass forming ability (GFA), making them attractive for certain structural applications. Great success in improving critical diameters of BMGs above 20 mm has been achieved in Zr, Pd, Y, Mg and La-based alloys. However, their main drawback, catastrophic failure through unhindered shear banding, has not been conquered, significantly limiting their structural reliability. Plenty of effort has been made recently to enhance their plasticity. For instance, BMG/crystal composites were found to possess some tensile ductility, since the interaction of glass matrix and second phase crystalline particles effectively inhibit the propagation of shear bands. Pre-straining of BMGs by cold-rolling, compression and surface shot-peening was also found to lead improved plastic strain due to the introduction of shear bands and compressive residual stresses. Interestingly, a number of monolithic BMGs showing remarkable compressive plasticity emerged due to (a) high Poisson's ratio; (b) chemical and microstructural inhomogeneity including phase separation, soft and hard regions with the same composition; (c) in-situ nanocrystallization during deformation; (d) more free volume by cooling faster or minor alloying. These hypotheses have not been fully verified, but it still provides instructive clues to enhance the plasticity of monolithic BMGs.
Recently, a series of Zr-(Cu,Ag)-Al BMGs with diameters at least 20 mm was developed, and even 25 g ingots became full glass upon slow cooling in an arc-melting machine in a wide Zr-(Cu,Ag)-Al composition range. These Zr-(Cu,Ag)-Al BMGs still suffer from low plasticity. Therefore, further development of Zr-(Cu,Ag)-Al alloys, simultaneously having good plasticity and relatively high GFA, is desirable. In the present work, a systematic composition tuning in the Zr-(Cu,Ag)-Al alloy system was carried out. After testing more than 100 alloys with fine composition variations, we successfully dig out one composition, which can form 1 mm thick and 10 mm wide BMG plates exhibiting distinct plasticity under both bending and compression. The thermal and mechanical properties, as well as atomic structure for the newly-developed Zr-Cu-Ag-Al BMG are presented. The intrinsic plastic deformability of the new BMG is discussed from the aspects of micro-and atomic structure. In comparison with Zr_(46)Cu_(37.6)Ag_(8.4)Al_8, the increase of Zr content in Zr53.8Cu31.6Ag7,oAl7.6 results in the increased portion of Zr-Zr atomic pair in the nearest shell of a pair distribution function. Steep peak profile on the right side of the pair distribution function in Zr_(53.8)Cu_(31.6)Ag_(7.0)A_(l7.6) suggests that more atoms are involved upon yielding and the opportunity of forming more shear bands increases. This finding may provide useful guideline for the development of plastic metallic glasses from the structural aspect.
最近,一系列直径20mm以上的ZrCuAgAl大块非晶合金被开发出来,这些合金非晶形成能力极强,仅仅通过电弧熔炼后的缓慢冷却,25克重的合金锭子就可以形成完全的非晶。但是这些非晶然后存在着塑性变形能力较差的致命问题,因此在该体系中开发出兼具良好的非晶形成能力以及出色的塑性变形能力的新型合金是非常有价值和意义的。在本项工作中,我们通过成分选择,在一百多个成分点中最终挖掘出了一个理想的合金,该合金可以很容易的通过铜模吸铸的方法制备出长10mm厚1mm的非晶合金,并且所制备的非晶合金表现出了良好的压缩塑性和弯曲塑性。为了进一步了解这种非晶合金,我们对其热学性能,力学性能以及原子结构进行了表征,并且从微观尺度和宏观尺度对该合金的塑性本质进行了探索。通过与Zr_(46)Cu_(37.6)Ag_(8.4)Al_8(形成能力最强成分)的对比,我们发现,新开发的Zr_(53.8)Cu_(31.6)Ag_(7.0)A_(l7.6)非晶合金由于含有Zr原子较多,从而使得径向分布函数中最近邻壳层中Zr-Zr原子对较多,这也使得径向分布函数第一峰右侧曲线较陡,从而使得变形过程中卷入变形的原子数量增多同时也增加了多条剪切带产生的可能性。该发现可能从结构角度对于非晶合金塑性变形能力的提高提供有效的指导。
Bulk metallic glasses (BMGs) combine superior mechanical properties such as high strength and large elastic strain with excellent glass forming ability (GFA), making them attractive for certain structural applications. Great success in improving critical diameters of BMGs above 20 mm has been achieved in Zr, Pd, Y, Mg and La-based alloys. However, their main drawback, catastrophic failure through unhindered shear banding, has not been conquered, significantly limiting their structural reliability. Plenty of effort has been made recently to enhance their plasticity. For instance, BMG/crystal composites were found to possess some tensile ductility, since the interaction of glass matrix and second phase crystalline particles effectively inhibit the propagation of shear bands. Pre-straining of BMGs by cold-rolling, compression and surface shot-peening was also found to lead improved plastic strain due to the introduction of shear bands and compressive residual stresses. Interestingly, a number of monolithic BMGs showing remarkable compressive plasticity emerged due to (a) high Poisson's ratio; (b) chemical and microstructural inhomogeneity including phase separation, soft and hard regions with the same composition; (c) in-situ nanocrystallization during deformation; (d) more free volume by cooling faster or minor alloying. These hypotheses have not been fully verified, but it still provides instructive clues to enhance the plasticity of monolithic BMGs.
Recently, a series of Zr-(Cu,Ag)-Al BMGs with diameters at least 20 mm was developed, and even 25 g ingots became full glass upon slow cooling in an arc-melting machine in a wide Zr-(Cu,Ag)-Al composition range. These Zr-(Cu,Ag)-Al BMGs still suffer from low plasticity. Therefore, further development of Zr-(Cu,Ag)-Al alloys, simultaneously having good plasticity and relatively high GFA, is desirable. In the present work, a systematic composition tuning in the Zr-(Cu,Ag)-Al alloy system was carried out. After testing more than 100 alloys with fine composition variations, we successfully dig out one composition, which can form 1 mm thick and 10 mm wide BMG plates exhibiting distinct plasticity under both bending and compression. The thermal and mechanical properties, as well as atomic structure for the newly-developed Zr-Cu-Ag-Al BMG are presented. The intrinsic plastic deformability of the new BMG is discussed from the aspects of micro-and atomic structure. In comparison with Zr_(46)Cu_(37.6)Ag_(8.4)Al_8, the increase of Zr content in Zr53.8Cu31.6Ag7,oAl7.6 results in the increased portion of Zr-Zr atomic pair in the nearest shell of a pair distribution function. Steep peak profile on the right side of the pair distribution function in Zr_(53.8)Cu_(31.6)Ag_(7.0)A_(l7.6) suggests that more atoms are involved upon yielding and the opportunity of forming more shear bands increases. This finding may provide useful guideline for the development of plastic metallic glasses from the structural aspect.
引文
1. W. Klement, R.H. Willens, and P. Duwez, Non-Crystalline Structure in Solidified Gold-Silicon Alloys. Nature,1960.187(4740):p.869-870.
2. H.S. Chen and D. Turnbull, Formation, Stability and Structure of Palladium-Silicon Based Alloy Glasses. Acta Metallurgica,1969.17(8):p.1021-1031.
3. H.S. Chen, Thermodynamic Considerations on Formation and Stability of Metallic Glasses. Acta Metallurgica,1974.22(12):p.1505-1511.
4. H.W. Kui, A.L. Greer, and D. Turnbull, Formation of Bulk Metallic-Glass by Fluxing. Applied Physics Letters,1984.45(6):p.615-616.
5. A. Inoue, M. Kohinata, A.P. Tsai, and T. Masumoto, Mg-Ni-La Amorphous-Alloys with a Wide Supercooled Liquid Region. Materials Transactions Jim,1989.30(5):p.378-381.
6. A. Peker and W.L. Johnson, A Highly Processable Metallic-Glass Zr41.2Ti13.8Cu12.5Ni10.0Be22.5. Applied Physics Letters,1993.63(17):p.2342-2344.
7. Y.H. Liu, G. Wang, R.J. Wang, D.Q. Zhao, M.X. Pan, and W.H. Wang, Super plastic bulk metallic glasses at room temperature. Science,2007.315(5817):p.1385-1388.
8. D.C. Hofmann, J.Y. Suh, A. Wiest, G. Duan, M.L. Lind, M.D. Demetriou, and W.L. Johnson, Designing metallic glass matrix composites with high toughness and tensile ductility. Nature,2008.451(7182):p.1085-1090.
9 Lu Z P, Tan H,Ng S C, The correlation between reduced glass transition temperature and glass forming ability of bulk metallic glasses, Scripta Mater.,2000,42,667-669
10 A. Inoue and T. Zhang, Stabilization of supercooled liquid and bulk glassy alloys in ferrous and non-ferrous systems, J. Non-Cryst. Solids 1999,250-252,552-554.
11 Y. Li, S.C. Ng, C.K. Ong, H.H. Hung, and T.T. Goh, Glass forming ability of bulk glass forming alloys, Scrip. Mater.1997,36,783-787.
12 A. Inoue, Y. Kawamura and Y. Masumoto, Synthesis and properties of Ti-based bulk amorphous alloys with a large supercooled liquid region, Mater. Sci. Forum 1997, 233-234,147-150
13. Z.P. Lu and C.T. Liu, A new glass-forming ability criterion for bulk metallic glasses. Acta Materialia,2002.50(13):p.3501-3512.
14. Z.P. Lu and C.T. Liu, Glass formation criterion for various glass-forming systems. Physical Review Letters,2003.91(11):p.115505. 2000.42(7):p.667-673.
15. J.D. Bernal, Geometrical Approach to the Structure of Liquids. Nature,1959.183(4655): p.141-147.
16. L. Bragg and J.F. Nye, A Dynamical Model of a Crystal Structure. Proceedings of the Royal Society of London Series a-Mathematical and Physical Sciences,1947.190(1023): p.474-481.
17. D.B. Miracle, W.S. Sanders, and O.N. Senkov, The influence of efficient atomic packing on the constitution of metallic glasses. Philosophical Magazine,2003.83(20):p. 2409-2428.
18. H.W. Sheng, W.K. Luo, F.M. Alamgir, J.M. Bai, and E. Ma, Atomic packing and short-to-medium-range order in metallic glasses. Nature,2006.439(7075):p.419-425.
19. W.H. Wang, C. Dong, and C.H. Shek, Bulk metallic glasses. Materials Science & Engineering R-Reports,2004.44(2-3):p.45-89.
20. A. Inoue, N. Nishiyama, and T. Matsuda, Preparation of bulk glassy Pd40Ni10Cu30P20 alloy of 40 mm in diameter by water quenching. Materials Transactions Jim,1996.37(2): p.181-184.
21. G. Sunny, J. Lewandowski, and V. Prakash, Effects of annealing and specimen geometry on dynamic compression of a Zr-based bulk metallic glass. Journal of Materials Research, 2007.22(2):p.389-401.
22. R.D. Conner, R.B. Dandliker, and W.L. Johnson, Mechanical properties of tungsten and steel fiber reinforced Zr41.25Ti13.75Cu12.5Ni10Be22.5 metallic glass matrix composites. Acta Materialia,1998.46(17):p.6089-6102.
23. Q.P. Cao, J.F. Li, Y. Hu, A. Horsewell, J.Z. Jiang, and Y.H. Zhou, Deformation-strengthening during rolling Cu60Zr20Ti20 bulk metallic glass. Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing, 2007.457(1-2):p.94-99.
24. Q.P. Cao, J.F. Li, J.Z. Jiang, and Y.H. Zhou, Microstructure and stored energy evolutions during rolling of Cu60Zr20Ti20 bulk metallic glass. Journal of Non-Crystalline Solids, 2008.354(52-54):p.5353-5362.
25. Q.P. Cao, J.F. Li, Y.H. Zhou, A. Horsewell, and J.Z. Jiang, Free-volume evolution and its temperature dependence during rolling of Cu60Zr20Ti20 bulk metallic glass. Applied Physics Letters,2005.87(10):p.101901.
26. Q.P. Cao, J.F. Li, Y.H. Zhou, A. Horsewell, and J.Z. Jiang, Effect of rolling deformation on the microstructure of bulk Cu60Zr20Ti20 metallic glass and its crystallization. Acta Materialia,2006.54(16):p.4373-4383.
27. Q.P. Cao, J.F. Li, Y.H. Zhou, and J.Z. Jiang, Mechanically driven phase separation and corresponding microhardness change in Cu60Zr20Ti20 bulk metallic glass. Applied Physics Letters,2005.86(8):p.081913.
28. Q.P. Cao, J.F. Li, Y.H. Zhou, and J.Z. Jiang, Microstructure and microhardness evolutions of Cu47.5Zr47.5A15 bulk metallic glass processed by rolling. Scripta Materialia,2008. 59(6):p.673-676.
29. Q.P. Cao, J.W. Liu, K.J. Yang, F.Xu, Z.Q. Yao, A. Minkow, H.J. Fecht, J. Ivanisenko, L.Y. Chen, X.D. Wang, S.X. Qu, and J.Z. Jiang, Effect of pre-existing shear bands on the tensile mechanical properties of a bulk metallic glass. Acta Materialia(2009), DOI: 10.1016/j.actamat.2009.10.032
30. K.M. Flores, E. Sherer, A. Bharathula, H. Chen, and Y.C. Jean, Sub-nanometer open volume regions in a bulk metallic glass investigated by positron annihilation. Acta Materialia,2007.55(10):p.3403-3411.
31. H.J. Kim, J.C. Bae, E.S. Park, J.C. Lee, M.Y. Huh, and D.H. Kim, Evolution of temperature gradients during rolling of Cu54Ni6Zr22Ti18 bulk metallic glass in the super cooled liquid region. Journal of Materials Processing Technology,2007.187:p.798-800.
32. M.H. Lee, J.S. Park, J.H. Kim. D.H. Bae, W.T. Kim, and D.H. Kim, Mechanical behavior of Ni-based metallic glass matrix composites deformed by cold rolling. Materials Letters, 2004.58(26):p.3312-3315.
33. R. Martinez, G. Kumar, and J. Schroers, Hot rolling of bulk metallic glass in its supercooled liquid region. Scripta Materialia,2008.59(2):p.187-190.
34. E.S. Park, H.G Kang, J.C. Lee, M.Y. Huh, H.J. Kim, and J.C. Bae, Evolution of strain states during rolling of bulk metallic glass canned with crystalline copper. Journal of Materials Processing Technology,2007.187:p.783-785.
35. J.S. Park, H.K. Lim, J.H. Kim, H.J. Chang, W.T. Kim, D.H. Kim, and E. Fleury, In situ crystallization and enhanced mechanical properties of the Zr41.2Ti13.8Cu12.5Ni10Be22.5 alloy by cold rolling. Journal of Non-Crystalline Solids, 2005.351(24-25):p.2142-2146.
36. X.S. Xiao, S.S. Fang, Q. Wang, G.M. Wang, Q. Hua, and Y.D. Dong, Effect of hot rolling on thermal stability and microstructure of Zr52.5Al10NilOCu15Be12.5 bulk metallic glass. Materials Letters,2004.58(19):p.2357-2360.
37. Y. Yokoyama, Ductility improvement of Zr-Cu-Ni-Al glassy alloy. Journal of Non-Crystalline Solids,2003.316(1):p.104-113.
38. P.N. Zhang, J.F. Li, Y. Hu, and Y.H. Zhou, Effect of rolling on the microstructure and mechanical property of Zr52.5Cu17.9Ni14.6Al10Ti5 bulk metallic glass. Journal of Alloys and Compounds,2008.462(1-2):p.88-93.
39. P.N. Zhang, J.F. Li, Y. Hu, and Y.H. Zhou, Microstructural evolution during annealing and rolling Zr52.5Cu17.9Ni14.6Al10Ti5 bulk metallic glass. Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing,2009. 499(1-2):p.374-378.
40. A. Inoue, Stabilization of metallic supercooled liquid and bulk amorphous alloys. Acta Materialia,2000.48(1):p.279-306.
41. W.L. Johnson, Bulk glass-forming metallic alloys:Science and technology. Mrs Bulletin, 1999.24(10):p.42-56.
42. W.H. Wang, C. Dong, and C.H. Shek, Bulk metallic glasses. Materials Science & Engineering R-Reports,2004.44(2-3):p.45-89.
43. Hammersley AP, Svensson SO, Hanfland M, Fitch AN, Hausermann D. Two-dimensional detector software:from real detector to idealised image. HighPress Res 1996; 14:235.
44. Jeong IK, Thompson J, Proffen Th, Perez A, Billinge SJL. PDFgetX:a program for obtaining the atomic pair distribution function from X-ray powder diffraction data. J Appl Crystallogr 2001;34:536.
45. Park BJ, Chang HJ, Kim DH, Kim WT. In situ formation of two amorphous phases by liquid phase separation in Y-Ti-Al-Co alloy. Appl Phys Lett 2004;85:6353.
46. Kundig AA, Ohnuma M, Ping DH, Ohkubo T, Hono K. In situ formed two-phase metallic glass with surface fractal microstructure. Acta Mater 2004;52:2441.
47. Park ES, Jeong EY, Lee JK, Kwon AR, Gebert A, Schultz L, Chang HJ, Kim DH. In situ formation of two glassy phases in the Nd-Zr-Al-Co alloy system. Scripta Mater 2007;56:197.
48. Mattern N, Kuhn U, Gebert A, Gemming T, Zinkevich M, Wendrock H, Schultz L. Microstructure and thermal behavior of two-phase amorphous Ni-Nb-Y alloy. Scripta Mater 2005;53:271.
49. Wada T, Louzguine-Luzgin D, Inoue A. Preparation of Zr-based metallic glass nanowires and nanoparticles by selective etching. Scripta Mater 2007;57:901.
50. Park ES, Kyeong JS, Kim DH. Phase separation and improved plasticity by modulated heterogeneity in Cu-(Zr, Hf)-(Gd, Y)-A1 metallic glasses. Scripta Mater 2007;57:49.
51. Oh JC, Ohkubo T, Kim YC, Fleury E, Hono K. Phase separation in Cu43Zr43A17Ag7 bulk metallic glass. Scripta Mater 2005;53:165.
52. Mattern N, Goerigk G, Vainio U, Miller MK, Gemming T, Eckert J. Spinodal decomposition of Ni-Nb-Y metallic glasses. Acta Mater 2009;57:903.
53. Lewandowski JJ, Wang WH, Greer AL. Intrinsic plasticity or brittleness of metallic glasses Philos Mag Lett 2005;85:77.
54. Busch R, Schroers J, Wang WH, Thermodynamics and kinetics of bulk metallic glass. MRS Bulletin 2007;32:620.
55. Spaepen F. A microscopic mechanism for steady state inhomogeneous flow in metallic glasses. Acta Metall 1977;25:407.
56. Murali P, Ramamurty U. Embrittlement of a bulk metallic glass due to sub-Tg annealing. Acta Mater 2005;53:1467.
57. Raghavan R, Boopathy K, Ghisleni R, Pouchon MA, Ramamurty U. Ion irradiation enhances the mechanical performance of metallic glasses. Scripta Mater 2010;62:462.
58. Van den Beukel A, Sietsma J. The glass transition as a free volume related kinetic phenomenon. Acta Metall 1990;38:383.
59. Slipenyuk A, Eckert J. Correlation between enthalpy change and free volume reduction during structural relaxation of Zr55Cu30Al10Ni5 metallic glass. Scripta Mater 2004;50:39.
60. Mondal K, Ohkubo T, Toyama T, Nagai Y, Hasegawa M, Hono K. The effect of nanocrystallization and free volume on the room temperature plasticity of Zr-based bulk metallic glasses. Acta Mater 2008;56:5329.
61. Bhowmick R, Raghavan R, Chattopadhyay K, Ramamurty U. Plastic flow softening in a bulk metallic glass. Acta Mater 2006:54:4221.
62. Park KW, Lee CM, Wakeda M, Shibutani Y, Falk ML, Lee JC. Elastostatically induced structural disordering in amorphous alloys. Acta Mater 2008;56:5440.
63. Chen HS. The influence of quenching procedures on the kinetics of embrittlement in a Fe40Ni40B20 metallic glass. J Appl Phys 1978;49:3289.
64. Schermeyer D, Neuhauser H. Dilatometric measurements on metallic glass ribbons with a wide glass transition range. Mater Sci Eng A 1997;226-228:846.
65. Zhang L, Cheng YQ, Cao AJ, Xu J, Ma E. Bulk metallic glasses with large plasticity: Composition design from the structural perspective. Acta Mater 2009;57:1154.
66. Wang XD, Bednarcik J, Saksl K, Franz H, Cao QP, Jiang JZ. Tensile behavior of bulk metallic glasses by in situ x-ray diffraction. Appl Phys Lett 2007;91:081913.
67. Chen LY, Li BZ, Wang XD, Jiang F, Yang R, Liaw PK, Cao QP, Jiang JZ, in preparation
2. H.S. Chen and D. Turnbull, Formation, Stability and Structure of Palladium-Silicon Based Alloy Glasses. Acta Metallurgica,1969.17(8):p.1021-1031.
3. H.S. Chen, Thermodynamic Considerations on Formation and Stability of Metallic Glasses. Acta Metallurgica,1974.22(12):p.1505-1511.
4. H.W. Kui, A.L. Greer, and D. Turnbull, Formation of Bulk Metallic-Glass by Fluxing. Applied Physics Letters,1984.45(6):p.615-616.
5. A. Inoue, M. Kohinata, A.P. Tsai, and T. Masumoto, Mg-Ni-La Amorphous-Alloys with a Wide Supercooled Liquid Region. Materials Transactions Jim,1989.30(5):p.378-381.
6. A. Peker and W.L. Johnson, A Highly Processable Metallic-Glass Zr41.2Ti13.8Cu12.5Ni10.0Be22.5. Applied Physics Letters,1993.63(17):p.2342-2344.
7. Y.H. Liu, G. Wang, R.J. Wang, D.Q. Zhao, M.X. Pan, and W.H. Wang, Super plastic bulk metallic glasses at room temperature. Science,2007.315(5817):p.1385-1388.
8. D.C. Hofmann, J.Y. Suh, A. Wiest, G. Duan, M.L. Lind, M.D. Demetriou, and W.L. Johnson, Designing metallic glass matrix composites with high toughness and tensile ductility. Nature,2008.451(7182):p.1085-1090.
9 Lu Z P, Tan H,Ng S C, The correlation between reduced glass transition temperature and glass forming ability of bulk metallic glasses, Scripta Mater.,2000,42,667-669
10 A. Inoue and T. Zhang, Stabilization of supercooled liquid and bulk glassy alloys in ferrous and non-ferrous systems, J. Non-Cryst. Solids 1999,250-252,552-554.
11 Y. Li, S.C. Ng, C.K. Ong, H.H. Hung, and T.T. Goh, Glass forming ability of bulk glass forming alloys, Scrip. Mater.1997,36,783-787.
12 A. Inoue, Y. Kawamura and Y. Masumoto, Synthesis and properties of Ti-based bulk amorphous alloys with a large supercooled liquid region, Mater. Sci. Forum 1997, 233-234,147-150
13. Z.P. Lu and C.T. Liu, A new glass-forming ability criterion for bulk metallic glasses. Acta Materialia,2002.50(13):p.3501-3512.
14. Z.P. Lu and C.T. Liu, Glass formation criterion for various glass-forming systems. Physical Review Letters,2003.91(11):p.115505. 2000.42(7):p.667-673.
15. J.D. Bernal, Geometrical Approach to the Structure of Liquids. Nature,1959.183(4655): p.141-147.
16. L. Bragg and J.F. Nye, A Dynamical Model of a Crystal Structure. Proceedings of the Royal Society of London Series a-Mathematical and Physical Sciences,1947.190(1023): p.474-481.
17. D.B. Miracle, W.S. Sanders, and O.N. Senkov, The influence of efficient atomic packing on the constitution of metallic glasses. Philosophical Magazine,2003.83(20):p. 2409-2428.
18. H.W. Sheng, W.K. Luo, F.M. Alamgir, J.M. Bai, and E. Ma, Atomic packing and short-to-medium-range order in metallic glasses. Nature,2006.439(7075):p.419-425.
19. W.H. Wang, C. Dong, and C.H. Shek, Bulk metallic glasses. Materials Science & Engineering R-Reports,2004.44(2-3):p.45-89.
20. A. Inoue, N. Nishiyama, and T. Matsuda, Preparation of bulk glassy Pd40Ni10Cu30P20 alloy of 40 mm in diameter by water quenching. Materials Transactions Jim,1996.37(2): p.181-184.
21. G. Sunny, J. Lewandowski, and V. Prakash, Effects of annealing and specimen geometry on dynamic compression of a Zr-based bulk metallic glass. Journal of Materials Research, 2007.22(2):p.389-401.
22. R.D. Conner, R.B. Dandliker, and W.L. Johnson, Mechanical properties of tungsten and steel fiber reinforced Zr41.25Ti13.75Cu12.5Ni10Be22.5 metallic glass matrix composites. Acta Materialia,1998.46(17):p.6089-6102.
23. Q.P. Cao, J.F. Li, Y. Hu, A. Horsewell, J.Z. Jiang, and Y.H. Zhou, Deformation-strengthening during rolling Cu60Zr20Ti20 bulk metallic glass. Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing, 2007.457(1-2):p.94-99.
24. Q.P. Cao, J.F. Li, J.Z. Jiang, and Y.H. Zhou, Microstructure and stored energy evolutions during rolling of Cu60Zr20Ti20 bulk metallic glass. Journal of Non-Crystalline Solids, 2008.354(52-54):p.5353-5362.
25. Q.P. Cao, J.F. Li, Y.H. Zhou, A. Horsewell, and J.Z. Jiang, Free-volume evolution and its temperature dependence during rolling of Cu60Zr20Ti20 bulk metallic glass. Applied Physics Letters,2005.87(10):p.101901.
26. Q.P. Cao, J.F. Li, Y.H. Zhou, A. Horsewell, and J.Z. Jiang, Effect of rolling deformation on the microstructure of bulk Cu60Zr20Ti20 metallic glass and its crystallization. Acta Materialia,2006.54(16):p.4373-4383.
27. Q.P. Cao, J.F. Li, Y.H. Zhou, and J.Z. Jiang, Mechanically driven phase separation and corresponding microhardness change in Cu60Zr20Ti20 bulk metallic glass. Applied Physics Letters,2005.86(8):p.081913.
28. Q.P. Cao, J.F. Li, Y.H. Zhou, and J.Z. Jiang, Microstructure and microhardness evolutions of Cu47.5Zr47.5A15 bulk metallic glass processed by rolling. Scripta Materialia,2008. 59(6):p.673-676.
29. Q.P. Cao, J.W. Liu, K.J. Yang, F.Xu, Z.Q. Yao, A. Minkow, H.J. Fecht, J. Ivanisenko, L.Y. Chen, X.D. Wang, S.X. Qu, and J.Z. Jiang, Effect of pre-existing shear bands on the tensile mechanical properties of a bulk metallic glass. Acta Materialia(2009), DOI: 10.1016/j.actamat.2009.10.032
30. K.M. Flores, E. Sherer, A. Bharathula, H. Chen, and Y.C. Jean, Sub-nanometer open volume regions in a bulk metallic glass investigated by positron annihilation. Acta Materialia,2007.55(10):p.3403-3411.
31. H.J. Kim, J.C. Bae, E.S. Park, J.C. Lee, M.Y. Huh, and D.H. Kim, Evolution of temperature gradients during rolling of Cu54Ni6Zr22Ti18 bulk metallic glass in the super cooled liquid region. Journal of Materials Processing Technology,2007.187:p.798-800.
32. M.H. Lee, J.S. Park, J.H. Kim. D.H. Bae, W.T. Kim, and D.H. Kim, Mechanical behavior of Ni-based metallic glass matrix composites deformed by cold rolling. Materials Letters, 2004.58(26):p.3312-3315.
33. R. Martinez, G. Kumar, and J. Schroers, Hot rolling of bulk metallic glass in its supercooled liquid region. Scripta Materialia,2008.59(2):p.187-190.
34. E.S. Park, H.G Kang, J.C. Lee, M.Y. Huh, H.J. Kim, and J.C. Bae, Evolution of strain states during rolling of bulk metallic glass canned with crystalline copper. Journal of Materials Processing Technology,2007.187:p.783-785.
35. J.S. Park, H.K. Lim, J.H. Kim, H.J. Chang, W.T. Kim, D.H. Kim, and E. Fleury, In situ crystallization and enhanced mechanical properties of the Zr41.2Ti13.8Cu12.5Ni10Be22.5 alloy by cold rolling. Journal of Non-Crystalline Solids, 2005.351(24-25):p.2142-2146.
36. X.S. Xiao, S.S. Fang, Q. Wang, G.M. Wang, Q. Hua, and Y.D. Dong, Effect of hot rolling on thermal stability and microstructure of Zr52.5Al10NilOCu15Be12.5 bulk metallic glass. Materials Letters,2004.58(19):p.2357-2360.
37. Y. Yokoyama, Ductility improvement of Zr-Cu-Ni-Al glassy alloy. Journal of Non-Crystalline Solids,2003.316(1):p.104-113.
38. P.N. Zhang, J.F. Li, Y. Hu, and Y.H. Zhou, Effect of rolling on the microstructure and mechanical property of Zr52.5Cu17.9Ni14.6Al10Ti5 bulk metallic glass. Journal of Alloys and Compounds,2008.462(1-2):p.88-93.
39. P.N. Zhang, J.F. Li, Y. Hu, and Y.H. Zhou, Microstructural evolution during annealing and rolling Zr52.5Cu17.9Ni14.6Al10Ti5 bulk metallic glass. Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing,2009. 499(1-2):p.374-378.
40. A. Inoue, Stabilization of metallic supercooled liquid and bulk amorphous alloys. Acta Materialia,2000.48(1):p.279-306.
41. W.L. Johnson, Bulk glass-forming metallic alloys:Science and technology. Mrs Bulletin, 1999.24(10):p.42-56.
42. W.H. Wang, C. Dong, and C.H. Shek, Bulk metallic glasses. Materials Science & Engineering R-Reports,2004.44(2-3):p.45-89.
43. Hammersley AP, Svensson SO, Hanfland M, Fitch AN, Hausermann D. Two-dimensional detector software:from real detector to idealised image. HighPress Res 1996; 14:235.
44. Jeong IK, Thompson J, Proffen Th, Perez A, Billinge SJL. PDFgetX:a program for obtaining the atomic pair distribution function from X-ray powder diffraction data. J Appl Crystallogr 2001;34:536.
45. Park BJ, Chang HJ, Kim DH, Kim WT. In situ formation of two amorphous phases by liquid phase separation in Y-Ti-Al-Co alloy. Appl Phys Lett 2004;85:6353.
46. Kundig AA, Ohnuma M, Ping DH, Ohkubo T, Hono K. In situ formed two-phase metallic glass with surface fractal microstructure. Acta Mater 2004;52:2441.
47. Park ES, Jeong EY, Lee JK, Kwon AR, Gebert A, Schultz L, Chang HJ, Kim DH. In situ formation of two glassy phases in the Nd-Zr-Al-Co alloy system. Scripta Mater 2007;56:197.
48. Mattern N, Kuhn U, Gebert A, Gemming T, Zinkevich M, Wendrock H, Schultz L. Microstructure and thermal behavior of two-phase amorphous Ni-Nb-Y alloy. Scripta Mater 2005;53:271.
49. Wada T, Louzguine-Luzgin D, Inoue A. Preparation of Zr-based metallic glass nanowires and nanoparticles by selective etching. Scripta Mater 2007;57:901.
50. Park ES, Kyeong JS, Kim DH. Phase separation and improved plasticity by modulated heterogeneity in Cu-(Zr, Hf)-(Gd, Y)-A1 metallic glasses. Scripta Mater 2007;57:49.
51. Oh JC, Ohkubo T, Kim YC, Fleury E, Hono K. Phase separation in Cu43Zr43A17Ag7 bulk metallic glass. Scripta Mater 2005;53:165.
52. Mattern N, Goerigk G, Vainio U, Miller MK, Gemming T, Eckert J. Spinodal decomposition of Ni-Nb-Y metallic glasses. Acta Mater 2009;57:903.
53. Lewandowski JJ, Wang WH, Greer AL. Intrinsic plasticity or brittleness of metallic glasses Philos Mag Lett 2005;85:77.
54. Busch R, Schroers J, Wang WH, Thermodynamics and kinetics of bulk metallic glass. MRS Bulletin 2007;32:620.
55. Spaepen F. A microscopic mechanism for steady state inhomogeneous flow in metallic glasses. Acta Metall 1977;25:407.
56. Murali P, Ramamurty U. Embrittlement of a bulk metallic glass due to sub-Tg annealing. Acta Mater 2005;53:1467.
57. Raghavan R, Boopathy K, Ghisleni R, Pouchon MA, Ramamurty U. Ion irradiation enhances the mechanical performance of metallic glasses. Scripta Mater 2010;62:462.
58. Van den Beukel A, Sietsma J. The glass transition as a free volume related kinetic phenomenon. Acta Metall 1990;38:383.
59. Slipenyuk A, Eckert J. Correlation between enthalpy change and free volume reduction during structural relaxation of Zr55Cu30Al10Ni5 metallic glass. Scripta Mater 2004;50:39.
60. Mondal K, Ohkubo T, Toyama T, Nagai Y, Hasegawa M, Hono K. The effect of nanocrystallization and free volume on the room temperature plasticity of Zr-based bulk metallic glasses. Acta Mater 2008;56:5329.
61. Bhowmick R, Raghavan R, Chattopadhyay K, Ramamurty U. Plastic flow softening in a bulk metallic glass. Acta Mater 2006:54:4221.
62. Park KW, Lee CM, Wakeda M, Shibutani Y, Falk ML, Lee JC. Elastostatically induced structural disordering in amorphous alloys. Acta Mater 2008;56:5440.
63. Chen HS. The influence of quenching procedures on the kinetics of embrittlement in a Fe40Ni40B20 metallic glass. J Appl Phys 1978;49:3289.
64. Schermeyer D, Neuhauser H. Dilatometric measurements on metallic glass ribbons with a wide glass transition range. Mater Sci Eng A 1997;226-228:846.
65. Zhang L, Cheng YQ, Cao AJ, Xu J, Ma E. Bulk metallic glasses with large plasticity: Composition design from the structural perspective. Acta Mater 2009;57:1154.
66. Wang XD, Bednarcik J, Saksl K, Franz H, Cao QP, Jiang JZ. Tensile behavior of bulk metallic glasses by in situ x-ray diffraction. Appl Phys Lett 2007;91:081913.
67. Chen LY, Li BZ, Wang XD, Jiang F, Yang R, Liaw PK, Cao QP, Jiang JZ, in preparation