Effect of cooling rate on crystallization of metallic Zr-Cu-Ni glass

X-ray diffraction (XRD) and differential scanning calorimetry (DSC) were employed to investigate the effect of cooling rate on crystallization behavior of metallic Zr70Cu20Ni10 glass. It is found that all DSC traces of the metallic Zr70Cu20Ni10 glasses under different cooling rates exhibit two exothermic peaks, indicating that the crystallization of metallic Zr70Cu20Ni10 glass proceeds through a double-stage mode. In our previous studies, we have concluded that the first exothermic reaction mainly corresponds to the precipitation of the Zr2Cu phase, and the second one is mainly due to the formation of nanoscale Zr2Ni particles. It is observed that there exists a close relationship between the cooling rate and thermodynamic parameters of metallic Zr70Cu20Ni10 glass, such as the onset crystallization temperature 7, the first peak temperature T-p1 and the second one T-p2. The above three thermodynamic parameters reach a maximum when the surface velocity is 30 m/s. This effect is just similar to that of the Ni concentration, which has been discussed in our previous works. The activation energy for crystallization and the local Avrami exponent of metallic Zr-Cu-Ni glass under isothermal annealing conditions also exhibit a similar tendency with the cooling rate. (C) 2002 Elsevier Science B.V. All rights reserved.