Crystallisation process of Al 80 Fe 10 Ti 10 amorphous phase

Abstract

In the present study, crystallisation behaviours of the Al₈₀Fe₁₀Ti₁₀ amorphous phase (prepared by mechanical alloying) has been investigated using X-ray diffraction and differential thermal analysis techniques. It was found that Al₈₀Fe₁₀Ti₁₀ amorphous phase exhibits one-stage crystallisation on heating [amorphous to Al₁₃Fe₄, Al(Fe,Ti) and Al₅Fe₂ intermetallic phases]. The activation energies for crystallisation of Al₈₀Fe₁₀Ti₁₀ amorphous phase were determined as 326, 322, 351 and 301 kJ mol⁻¹ by means of the Kissinger–Akahira–Sunose, Flynn–Wall–Ozawa, Friedman and Afify equations respectively. Kinetic parameters such as Avarmi exponent or reaction order n and frequency factor K_o were also discussed. The reaction orders obtained for the crystallisation was ∼2·03, suggesting that a diffusion controlled crystallisation process with a decreasing nucleation rate was the crystallisation mechanism. The deduced K_o value for crystallisation peak was calculated to be 6·75×10¹⁰ s⁻¹.