Kinetic Analysis of Crystallization Behaviors in Zn38Mg12Ca32Yb18 Bulk Metallic Glass [Zn38Mg12Ca32Yb18大块金属玻璃的晶化动力学行为]
Résumé
The kinetics of crystallization of Zn38Mg12Ca32Yb18 bulk metallic glass was studied by differential scanning calorimetry (DSC) in both non-isothermal and isothermal (at different heating rates) modes. Under isochronal process, theoretical models were adopted to analyze the apparent activation energies for characteristic temperatures. The results indicate that the apparent activation energies for characteristic temperatures in the Zn38Mg12Ca32Yb18 bulk metallic glass by Kissinger model, Flynn-Wall-Ozawa (FWO) model and Augis-Bennett (AB) model are in good agreement with each other. Furthermore, crystallization transformation kinetics during isothermal process was analyzed by the Johnson-Mehl-Avrami (JMA) model. The Avrami exponent n ranges from 3.25 to 4.12 in the isothermal mode. It is noted that the activation energy corresponding to isothermal conditions calculated using Arrhenius equation is larger than the value calculated by the Kissinger method in isochronal conditions, because the energy barrier in isothermal annealing mode is higher than that of isochronal conditions. Copyright © 2019, Northwest Institute for Nonferrous Metal Research. Published by Elsevier BV. All rights reserved.
Mots clés
Crystallization behavior
Isotherms
Activation energy
Calcium alloys
Crystallization transformations
Kinetics
Metallic glass
Magnesium alloys
Kinetics of crystallization
Johnson-mehl-avrami
Isothermal annealing
Glass
Isothermal conditions
Differential scanning calorimetry
Crystallization kinetics
Chromium alloys
Calorimeters
Metals
Polymer blends
Ytterbium alloys
Zinc alloys
Apparent activation energy
Avrami exponent
Characteristic temperature