Document Type: Research Paper
Materials Engineering Faculty, Islamic Azad University, Najafabad Branch, Isfahan, Iran
Department of Materials Science and Engineering, Faculty of Engineering, Hamedan university of technology
In this study, the crystallization behavior of melt-spun Al87Ni10La3 amorphous phase was investigated by using X-ray diffraction and non-isothermal differential thermal analysis techniques. The results demonstrated that the amorphous phase exhibited two-stage crystallization on heating, i.e., at first step the amorphous phase transforms into α-Al phase and at second step Al11La3 and Al3Ni intermetallic phases precipitate, simultaneously. The activation energies of the crystallizations of the amorphous phase were evaluated by the Kissinger equation using the peak temperature of the exothermic reactions. The values of two-step crystallization activation energies were approximately 173.7±6 and 278.4±5 kJ/mol, respectively. The Avrami index was calculated for the first and second step of crystallizations and obtained 0.9 and 3.8 respectively. This kinetics investigation indicated that in the first step of crystallization of Al87Ni10La3 alloy, the nucleation rate decreases with time, and the crystallization is governed by a three-dimensional diffusion-controlled growth, while the second stage was in interface control regime.