Kinetics of α-Fe nano crystallization in Fe55Cr18Mo7B16C4 bulk amorphous alloy

In this research work, crystallization kinetics of Fe55Cr18Mo7B16C4 alloy was evaluated by X-ray diffraction, transmission electron microscopy observations and differential scanning calorimetric tests. In practice, crystallization and growth mechanisms were investigated using differential scanning calorimetric tests in four different heating rates. Results showed that a two -step crystallization process occurred in the alloy in which α-Fe phase was crystallized in the first step after annealing treatments. Activation energy for the first step of crystallization i.e. α-Fe was measured to be 276 (kj/mol) according to Kissinger model. Further, avrami exponent calculated from differential scanning calorimetric curves was 2 and a three -dimensional diffusion controlled mechanism with decreasing nucleation rate was observed in the alloy. It is also known from the transmission electron microscopy observations that crystalline α- Fe phase nucleated in the structure of the alloy in an average size of 10 nm and completely mottled morphology.