Phase transformation and crystallization kinetics of melt-spun Ni60Nb20Zr20 amorphous alloy
| Autor: | Ted B. Flanagan, Anjali Talekar, Michael D. Dolan, Wen-Ming Chien, Dhanesh Chandra, Joshua Lamb, Stephen N. Paglieri, Sang-Mun Kim, Narendra K. Pal |
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| Rok vydání: | 2012 |
| Předmět: |
Arrhenius equation
Materials science Amorphous metal Intermetallic Thermodynamics Activation energy Condensed Matter Physics Isothermal process Electronic Optical and Magnetic Materials law.invention symbols.namesake Crystallography Differential scanning calorimetry law Materials Chemistry Ceramics and Composites symbols Crystallization Glass transition |
| Zdroj: | Journal of Non-Crystalline Solids. 358:1165-1170 |
| ISSN: | 0022-3093 |
| Popis: | The glass transition and crystallization kinetics of melt-spun Ni60Nb20Zr20 amorphous alloy ribbons have been studied under non-isothermal and isothermal conditions using differential scanning calorimetry (DSC). The dependence of glass transition and crystallization temperatures on heating rates was analyzed by Lasocka's relationship. The activation energies of crystallization, Ex, were determined to be 499.5 kJ/mol and 488.6 kJ/mol using the Kissinger and Ozawa equations, respectively. The Johnson–Mehl–Avrami equation has also been applied to the isothermal kinetics and the Avrami exponents are in the range of 1.92–2.47 indicating a diffusion-controlled three-dimensional growth mechanism. The activation energy obtained from the Arrhenius equation in the isothermal process was calculated to be Ex = 419.5 kJ/mol. The corresponding three dimensional (3D) time–temperature–transformation (TTT) diagram of crystallization for the alloy has been drawn which provides the information about transformation at a particular temperature. In addition, the intermetallic phases and morphology after thermal treatment have been identified by X-ray diffraction (XRD) and scanning electron microscope (SEM). |
| Databáze: | OpenAIRE |
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