| A new technics of crystallization of Fe-based alloy(Fe73.5Cu1Nb3Si13.5B9) ribbon has been obtained, and new models of crystallization of Fe-based alloy ribbon have been constructed. The work was as follows.一, Longitudinally driven giant magnetoimpedance(LDGMI) effect of Fe-based alloy ribbons annealed at different annealing parameters(temperature, stress) have been studied systemically. It was found that, ①The maximum GMI ratio of Fe-based alloy ribbons has been obtained when annealed at the parameters, which were not 540℃ without stress as people think, but 500℃ with 171Mpa tensile stress exerted. ②when the annealing temperature was between 500℃-530℃, there was a suitable stress for maximum GMI ratio in every temperature.二, A new experimental method by observation of the images of the cross section samples (CSS) of Fe-based alloy ribbons with atomic force microscopy (AFM) has been set up. The mesostructure in the CSS of Fe-based alloy ribbons annealed in different annealing parameters (temperature, stress) was investigated. It was found that, ①There were crystalline grains (coated with amorphous shell) gathering in Fe-based nanocrystalline ribbons. ②The rule of the temperature dependence of the gathering of the coated crystalline grains has been found. With the increase in annealing temperature, the direction excellence of the coated crystalline grains gathering (EGG) weakened gradually until it disappeared, and its size increased gradually. ③The rule of the tensile stress dependence of the gathering of the coated crystalline grains has been found. As the external tensile stress increased, the EGG get obvious gradually, its range expanded gradually from the free face area (FFA) to the sticking roller face area(SRFA), the angle between the EGG and the transverse axial direction (TAD) in the FFA reduced, and the grain size in the FFA increased... |
