Effect of annealing on the kinetics of glass transition and crystallization in Co–Fe–Ta–B amorphous alloy

• Published in: Journal of alloys and compounds Vol. 429; no. 1; pp. 104 - 110
• Main Authors: Yuan, Zi-Zhou, Wang, Bing-Xia, Tong, Ya-Dong, Chen, Xue-Ding
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.02.2007; Elsevier
• Subjects: Amorphous materials; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Crystallization; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; Glass transitions; Growth from solid phases (including multiphase diffusion and recrystallization); Kinetics; Materials science; Methods of crystal growth; physics of crystal growth; Physics; Specific phase transitions; Thermal analysis; Amorphous materials; Kinetics; Thermal analysis; Crystallization; Differential scanning calorimetry; Annealing; Tantalum alloys; Amorphous alloy; Heat treatments; Glass transition; Kinetics: Thermal analysis; Growth mechanism; Short-range order; Activation energy; Cobalt alloys; Transition element alloys
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2006.03.082

The effects of pre-annealing near glass transition temperature on the kinetics of following glass transition and crystallization for Co 43Fe 20Ta 5.5B 31.5 amorphous alloy have been investigated by non-isothermal differential scanning calorimetry. It was found that pre-annealing diminished the kinetic effect of glass transition, whereas the kinetics effect of crystallization was not significantly affected by pre-annealing. The glass transition was delayed by pre-annealing, which is characterized by having higher glass transition temperature and activation energy of glass transition for annealed samples. The crystallization peak temperature corresponding to a selected heating rate was lower, but the activation energy of crystallization was higher for annealed samples than that for as-quenched samples. The contradiction between them was discussed in terms of the formation of clusters in the short-range order that had a similar structure of crystals precipitated from amorphous matrix and the small diffusivity in the annealed alloy. Based on Matusita's equation, it was found that the crystallization of as-quenched Co 43Fe 20Ta 5.5B 31.5 amorphous alloy was governed by diffusion-controlled two-dimensional growth of particles nucleated at constant rate.