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A Kinetic Study of the Non-isothermal Crystallization of a Zr-Based Bulk Metallic Glass |
| LIU Lin1;WU Zhi-Fang1;CHEN Li2 |
| 1The State Key Laboratory of Plastic Forming Stimulation and Die and Mould Technology, Huazhong University of Science and Technology, Wuhan 430074
2Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 |
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| Cite this article: |
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LIU Lin, WU Zhi-Fang, CHEN Li 2002 Chin. Phys. Lett. 19 1483-1486 |
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Abstract The kinetics of the non-isothermal crystallization of Zr55Cu30Al10Ni5 bulk metallic glass was studied by differential scanning calorimetry in the mode of continuos heating. It is found that both glass transition and crystallization of the amorphous alloy behave in a marked kinetic nature. The activation energy E and frequency factor k0 for crystallization were determined by the Kissinger method, which yields E = 230kJ/mol, and k0 = 4.2 x 1012/s. The value of k0 is much smaller than that for conventional amorphous alloys, demonstrating that the atomic mobility in bulk metallic glasses is quite sluggish. The crystallization mechanism in the non-isothermal process was analysed in terms of the kinetic transformation equation for the solid-state phase transformation. This reveals that the crystallization kinetic function f(x) for Zr55Cu30Al10Ni5 can be described by the Johnson-Mehl-Avrami equation, i.e. f(x) = (1-x) [-\ln (1-x)](n-1)/n, with n = 1.75. This indicates that the non-isothermal crystallization of Zr55Cu30Al10Ni5 bulk metallic glass is governed by diffusion-controlled one-dimensional growth. Finally, the different crystallization mechanisms in the isothermal and non-isothermal processes are discussed.
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| Keywords:
61.43.Dq
64.60.Ht
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Published: 01 October 2002
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| PACS: |
61.43.Dq
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(Amorphous semiconductors, metals, and alloys)
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64.60.Ht
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(Dynamic critical phenomena)
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