Differential scanning calorimetry (DSC) was used to investigate the thermal behavior and non-isothermal crystallization kinetics of the Fe
67Nb
5B
28 metallic glasses prepared by melt-spinning method. DSC traces exhibit that the crystallization takes place through a single exothermic reaction, and it processes a good thermal stability in thermodynamics. The activation energies for nucleation and grain growth processes were calculated to be 536 ± 22 and 559 ± 20 kJ mol
?1 by Kissinger equation, respectively, and 551 ± 24 and 574 ± 20 kJ mol
?1 by Ozawa equation, respectively. It means that the grain growth process is more difficult than the nucleation process. The variation of local Avrami exponent
n(
x) with crystallized fraction
x demonstrates that the crystallization mechanism varies at different stages. The
n(
x) is larger than 2.5 at the initial stage of 0 <
x < 0.3, implying a mechanism of diffusion-controlled three-dimensional growth with increasing nucleation rate. The
n(
x) decreases from 2.5 to 1.5 in the range of 0.3 <
x < 0.65, suggesting that the crystallization belongs to three-dimensional nucleation and grain growth with decreasing nucleation rate. And
n(
x) lies between 1.0 and 1.5 in the range of 0.65 <
x < 0.95, indicating that the crystallization corresponds to the growth of particles with an appreciable initial volume. Low-temperature annealing corresponds to the precipitation of α-Fe, Fe
2B, and Fe
23B
6 phases, and further annealing leads to the formation of α-Fe, Fe
2B, and FeNbB phases. The magnetic properties in relation to microstructure change of the Fe
67Nb
5B
28 metallic glasses are discussed.
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