Abstract
The crystallization behaviour and microstructural development during the annealing of amorphous melt-spun Fe 63Cr 18Ti 4B 15 ribbons have been investigated by a combination of differential scanning calorimetry, transmission electron microscopy (TEM) and energy dispersive X-ray microanalysis. The crystallization onset, peak, and finish temperatures of the amorphous alloy are 571, 589 and 600 °C respectively during continuous heating at 5 °C min −1. The incubation time for the onset of crystallization obeys the Arrhenius law, with an activation energy of 1.5 eV. The crystallization process obeys the Johnson-Mehl-Avrami law, with an Avrami exponent near to three, indicating near-spherical 3D growth on pre-existing nuclei, producing an equiaxed structure as observed by TEM. The activation energy for crystal growth is 1.8 eV. Isothermal annealing for 2 h at temperatures in the range 550–1000 °C produces microstructures consisting of a mixture of ferrite, faulted Cr-rich body centre tetragonal M 2B boride particles and small Ti-rich primitive tetragonal M 3B 2 boride particles depending on the annealing temperature.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have