| In this thesis,we analyze the effects of AC magnetic field on the magnetic,mechanical,electrochemical properties and structure of Fe78Si9B13 amorphous ribbons,and the effects of magnetic anisotropy,crystallization behavior and heterogeneous regions are also investigated by X-ray diffractometry(XRD),scanning electron microscopy(SEM),differential scanning calorimeter(DSC),vibrating sample magnetometer(VSM).electrochemical workstation,paramagnetic resonance(ESR)and other equipment.It is shown by DSC analysis data that the precipitation of ?-Fe(Si)phase is controlled by diffusion(?=0.5),and the precipitation of eutectic phase of ?-Fe and Fe2B phase or Fe2B phase is controlled by interface(?=1).The growth mode of ?-Fe(Si)phase is sensitive to the magnetic force after treatment under the low field and the growth activation energy or nucleation activation energy of the samples have changed greatly,but the growth mode of eutectic phase of?-Fe and Fe2B or Fe2B phase is insensitive to the response of magnetic force(change of nuclear activation energy and growth energy are not obvious).However,A large change(growth activation can be significantly reduced and nucleation activation can be increased first and then decreased)has been discovered after treatment under the high field.Apparent activation energy activation can be reduced,then increased and decreased with the increase of field.This is due to the existence of three processes inside the material under the AC magnetic field.The low magnetic field in the first process makes the ability of atomic diffusion stronger,and the second process is that the solute atoms begin to segregate and enrich while the magnetic field is increasing.The third process is,the diffusion capacity of the inert zone is also enhanced with large alternating magnetic field.It can be found that the degree of dispersion of dM/dH?1/H3 fitting curve increases and then decreases along the X-Direction near the origin,and the opposite trend along the Y-Direction when the magnetic field increases through the analysis of the magnetic properties.Large degree of dispersion means large internal stress or non-magnetic doping.We can find log(Ms2/xir)?|K| has a linear relationship.And you can get T2z(sample No.1)<T2h(sample No.1),T2z(sample No.3)>T2h(sample No.3),T2z(sample No.5)<T2h(sample No.5)by paramagnetic resonance data.Larger T2 may be due to the transition of similar small magnetic moments(more neighboring cores).It also reflects the enrichment process of solute atoms in the sample,which means that there is an uneven structure inside the material itself or after the alternating field treatment.The distribution of uneven regions within the material significantly affects the plasticity of the material.The distribution of the uneven zone perpendicular to the direction of the shear band is more reflective of the plasticity of the material:In the original strip,the type of uneven distribution along the X direction makes the poor tensile plasticity along X direction;the type of uneven zone distribution along the Y direction obstructs the extension of the shear band,resulting in better tensile ductility in the Y direction;the plasticity of the transverse-field samples are improved due to the change in the type of distribution along the X direction after the lower alternating magnetic field treatment,but there is the opposite for longitudinal-field samples;the content of uneven zone is generally reduced in the case of high-field treatment,so the plasticity is reduced whether it is transverse-field sample or longitudinal-field sample. |
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