On non-isothermal kinetics of two Cu-based bulk metallic glasses
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In this paper, two Cu-based bulk metallic glasses, Cu55Zr37Ti8 and Cu61Zr34Ti5, have been evaluated in thermodynamics and kinetics. The activation energies with the constant values were generalized by different theoretical models. The E x of Cu55Zr37Ti8 and Cu61Zr34Ti5 are 319 ± 12 and 359 ± 12 kJ mol−1, respectively, implying that the as-cast alloys have a good stability in thermodynamics. On the other hand, variable activation energies were also determined using Kissinger–Akahira–Sunose method, Ozawa–Flynn–Wall method, and Friedman’s method. The results showed that the Ea(x) at the beginning of the crystallization are higher than that at the end of the crystallization in the first exothermic peak. By introducing the local Avrami exponent, n(x), the growth and nucleation mechanisms were discussed. Furthermore, the effects of different activation energies on local Avrami exponent were also given a discussion.
KeywordsCu-based bulk metallic glass Non-isothermal kinetics Activation energy Local Avrami exponent
Thanks for financial support from the National Natural Science Foundation of China (Grant no. 50971041).
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