Stress relief by annealing under external stress in Fe-based metallic glasses

Abstract

The effects of stress relief on the magnetic characteristics of Fe-based metallic glass (MG) ribbons are investigated under external stress through various annealing treatments. We found that long-time annealing treatments benefit for making softer magnetic MGs under applied bending stress. We show that the irreversible domain wall movement region and the irreversible domain wall rotation region in the M-H curve represent the stress relief, which can be well reflected by the demagnified magnetic anisotropy. The magnetic coercivity and effective permeability variations in the lower frequency regime also represent the stress relief state. These observations have implications for understanding the relationship between the stress relief, microstructure change, and magnetic softness in magnetic MGs and might be helpful for the performance improvement of the ferromagnetic glassy materials.

Study on the magnetic shielding properties of nanocrystalline strips under bending stress

“…The σ is calculated according to equation (3), and we can clearly see that the larger Δr = r i0 -r i1 is, the larger the bending stress σ of the nanocrystalline core in the bending direction. This phenomenon is consistent with previous reports in the literature [11,15].…”

“…Previous studies have shown that magnetostriction, stress, and temperature may be the origin of magnetic anisotropy [15,26,27]. E k (magnetic anisotropy energy) is defined as the energy required to reach magnetic saturation from a demagnetized state, as shown in equation (11) and the figure 4(a) [11].…”

“…Fe-based nanocrystalline alloys prepared from amorphous precursors were introduced in 1988 [10]. So far, extensive experimentations and theoretical investigations in amorphous and nanocrystalline strips have been devoted to the relationship between internal stresses and magnetic parameters such as permeability [11,12], magnetic anisotropy [11,13], and coercivity [11,14]. Despite these efforts, the quantitative understanding of the contribution of stress to the magnetization process and the effect of stress relief on the magnetic properties of amorphous and nanocrystalline crystals was unknown.…”

“…Despite these efforts, the quantitative understanding of the contribution of stress to the magnetization process and the effect of stress relief on the magnetic properties of amorphous and nanocrystalline crystals was unknown. To quantitatively characterize the effect of external stresses on Fe-based amorphous and nanocrystalline, M.C.Ri [11,15] introduced bending stresses along the bending direction by uniformly rewinding annealed amorphous alloy rings with different-sized radii into smaller rings of the same size (tension on outer surface and compression on inner surface), and then evaluated the relationship between the bending stresses and radius changes by using the inverse change of the radius as a measure of strain through Hooke's law, i.e. r r…”

The Effect of Annealing on the Soft Magnetic Properties and Microstructure of Fe82Si2B13P1C3 Amorphous Iron Cores

“…The high stress levels during the extremely cold process of quenching result in magnetic domains with irregular shapes, varying widths, disordered orientations and the presence of fine fingerprint domains. Residual stress has a detrimental effect on magnetic properties, and annealing has been proven to be effective in relieving internal stress and enhancing the magnetic properties of the ribbons [ 23 ]. Annealing induces structural relaxation and the release of internal stress in the amorphous strip, causing the magnetic domains within the strip to align along the direction of the easily magnetized axis, which is parallel to the strip’s length.…”