Microstructure and crystallization kinetics of amorphous metallic alloy: Fe54Co26Si6B14

Abstract Magnetic properties and microstructural evolution of the amorphous Co26Fe54B14Si6 alloy during thermal annealing were characterized using transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). TEM demonstrated that, similar to the Co-free iron glass system, the amorphous Co26Fe54B14Si6 alloy crystallizes through two stages: initial development of α-(Fe,Co) dendrites and eutectic reaction due to the solute enrichment. Through the DSC analysis, the activation energy for the initial dendritic crystallization was determined to be 208 kJ/mol, which is considerably lower than that of Co-free system, indicating that the addition of Co in the glass system destabilize the amorphous structure and promotes devitrification. The magnetic property of the material was also correlated to the microstructure developed during the crystallization process. The coercivity of the material was observed to increase steadily as the crystallization process proceeded due to increasing density of α-(Fe,Co) crystallites providing domain wall pinning sites.