The effects of magnetic field annealing on the magnetic properties and microstructure of Fe80Si9B11 amorphous alloys

The present work investigated the effects of magnetic field annealing on the magnetic properties, mechanical properties and microstructure of the Fe80Si9B11 amorphous alloys. The results show that the soft magnetic properties (SMPs) were obviously improved after the samples were annealed below the crystallization temperature with a 1 T magnetic field. The atom probe tomography (APT) results showed that the magnetic field has little effect on the element distribution of the annealed samples at 653 K. The results of XRD and TEM showed that the 653 K x 0 T sample included a few nanocrystals and an amorphous matrix while the 653 K x 1 T sample still retained an amorphous structure. It is worth noting that a large number of spherical symmetry clusters and a small number of translational symmetry clusters can be observed in the 653 K x 1 T sample. Many translational symmetry clusters, and a few spherical symmetry clusters, can be identified in the 693 K x 1 T sample. Both good soft magnetic properties (SMPs) and acceptable mechanical properties were obtained after the sample was annealed at 653 K. Compared with that of the as-cast sample, the values of maximum magnetic flux intensity (B-m), elastic modulus (E-r) and hardness increased by 13.7%, 36.6% and 9.4%, respectively, while the values of coercivity (H-c) and hysteresis loss (P-u) decreased by 71.5% and 68.2%, respectively. After the sample was annealed at 693 K, the SMPs exhibited a deterioration, and Er and hardness also dropped sharply. Based on the above results, the mechanism of the microstructural change for Fe80Si9B11 amorphous alloys related to the magnetic field annealing conditions was proposed. The relationship between the soft magnetic properties, mechanical properties, and the microstructure of the sample was also discussed. This paper provides a basis for the further improvement the SMPs of the Fe80Si9B11 amorphous ribbons by controlling the microstructure.