Kinetics and mechanism of structural transformations of Fe75Ni2Si8B13C2 amorphous alloy induced by thermal treatment

Abstract

The kinetics of structural transformations of the Fe75Ni2Si8B13C2 amorphous alloy under non-isothermal conditions was studied. It was shown that the amorphous alloy was stable up to 723 K, when multi-step structural transformations start, involving formation of stable alpha-Fe(Si) and Fe2B crystalline phases, and a metastable Fe15Si3B2 phase, their growth and the decomposition of the metastable phase into the two stable phases. Peakfit software was used to resolve the overlapping peaks corresponding to different crystallization steps, at different heating rates. The kinetic parameters corresponding to each of the steps were evaluated and kinetic triplet for every single step was established (g(alpha) = [-ln(1 - alpha)](1/3), E-a = 375.1 +/- 0.8 kJ/mol and In A = 56.2 +/- 1.0 for step 1; E-a = 341.6 +/- 0.5 kJ/mol and In A = 49.3 +/- 0.5 for step 2). The effects of structural transformations on the established kinetic model were discussed in detail.