Sub-Tg annealing effect on the kinetics of glass transition and crystallization for a Ti-Zr-Be-Fe bulk metallic glass
Abstract
The influence of sub-Tg pre-annealing on the kinetics of glass transition and crystallization of a lightweight Ti41Zr25Be28Fe6 bulk metallic glass (BMG) has been investigated by isochronal and isothermal differential scanning calorimetry tests. It was found that sub-Tg annealing obviously enlarges the supercooled liquid region of Ti41Zr25Be28Fe6 BMG, indicating an enhanced thermal stability. The activation energies for glass transition and crystallization of the as-cast and pre-annealed samples have been calculated and compared. The pre-annealed samples possess smaller values of fragility parameter and longer incubation times upon isothermal heating compared with the as-cast sample, indicating a retarded crystallization process. The isothermal crystallization kinetics of the samples with different annealed states has been investigated in terms of the Johnson-Mehl-Avrami equation and local Avrami exponent. The current study reveals a clear sub-Tg annealing effect on the kinetics of glass transition and crystallization of Ti41Zr25Be28Fe6 glassy alloy and the possible mechanisms have also been proposed.
- Publication:
-
Journal of Non Crystalline Solids
- Pub Date:
- October 2017
- DOI:
- 10.1016/j.jnoncrysol.2017.08.007
- Bibcode:
- 2017JNCS..473..132W
- Keywords:
-
- Bulk metallic glasses;
- Annealing;
- Glass transition;
- Crystallization kinetics;
- Structural relaxation