The crystallization study of glassy thin film Ti-base alloy

Amorphous Ti45Cu35Zr15Sn5 (at.%) thin-films metallic glass was prepared by non-reactive magnetron sputtering in pure argon at room temperature. The microstructural evaluation shows that the as-deposited thin films have a glassy structure. In this paper, the kinetics of isochronal and isothermal differential scanning calorimetry of Ti45Cu35Zr15Sn5 amorphous alloy was analyzed to understand the mechanism of crystallization. The crystallization process constituted of two exothermic transformations occurring from 723 to 863 K. The activation energy of the crystallization was obtained by the Kissinger-kahira-Sunose method. The results show that the activation energy of the Ti45Cu35Zr15Sn5 film for the first and the second crystallization steps were 370 and 300 kJ/mol, respectively. In the case of isothermal crystallization, the crystallization kinetics was modeled by the Johnson–Mehl–Avrami-Kolmogorov (JMAK) equation. The Avrami exponents were calculated to be about 2. The local Avrami exponents indicating that the crystallization mechanism of Ti45Cu35Zr15Sn5 freestanding thin films is three-dimensional growth with either a decreasing nucleation rate.