Kinetics analysis of the isothermal crystallization of Cu55Zr45 metallic glass by differential scanning calorimetry |
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Authors: | Qian Gao Zengyun Jian |
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Institution: | School of Materials and Chemical Engineering, Xi'an Technological University, Xi'an, Shaanxi, People's Republic of China |
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Abstract: | The crystallization kinetics of Cu55Zr45 (at%) glassy alloy is studied under isothermal condition using differential scanning calorimetry (DSC). The plot of correlation between the crystallized volume fraction α and annealing time t shows a sigmoid-type curve, which is steeper with higher annealing temperature. Furthermore, in isothermal crystallization condition, local activation energy Eα values, determined using the Arrhenius equation, range from 181.1 to 187.8 kJ/mol, which is nearly a constant. The local Avrami exponent n(α) values, obtained by the Johnson-Mehl-Avrami equation, which range from 2.2 to 4.0 at different annealing temeperatures, which indicates that the crystallization mechanism is diffusion-controlled transformation. Moreover, n(α) becomes greater with increasing annealing temperature, which indicates that annealing temperature can affect nucleation rate and growth type. |
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Keywords: | crystallization kinetics crystallization mechanism isothermal crystallization local activation energy metallic glass |
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