Crystallization kinetics of amorphous Sm8Fe85Si2C5 alloy

Abstract

The crystallization kinetics of amorphous Sm8Fe85Si2C5 alloy has been investigated. As the alloy is heated to 900 °C, the crystalline phases of the alloy are composed of α-Fe phase and Sm2(Fe, Si)17Cx. At the beginning of crystallization the activation energy of the α-Fe phase is about 425 kJ/mol, it remains relatively constant as the crystallized fraction of the α-Fe phase is below 70%, and then it declines with increasing the crystallized fraction. When the crystallized fraction of the Sm2(Fe, Si)17Cx is below 50%, the activation energy of crystallization of the phase remains between 518 and 530 kJ/mol, and then decreases with the crystallized fraction. The crystallization behavior of the α-Fe phase and Sm2(Fe, Si)17Cx essentially results in the formation of an α-Fe/Sm2(Fe, Si)17Cx composite microstructure with a coarse grain size in annealed Sm8Fe85Si2C5 alloy, which is attributed to a difficult nucleation and an easy growth for both the α-Fe phase and Sm2(Fe, Si)17Cx in the alloy. Cu and Nb can be used to change the crystallization behavior of the α-Fe phase in the amorphous Sm8Fe85Si2C5 alloy, which is helpful to the formation of the α-Fe/Sm2(Fe, Si)17Cx nanocomposite microstructure with a fine grain size for the α-Fe phase in the alloy.