Magneto-mechanical coupling effect of ferromagnetic materials: Test characteristics and theoretical model

Abstract

The magneto-mechanical coupling effect of ferromagnetic materials is the result of macroscopic influence of mechanical properties on magnetic properties under the combined action of stress field and applied magnetic field, which essentially can be attributed to the change of material properties caused by the transformation of microscopic magnetic domain structures. The effect of applied magnetic field is mainly manifested as the change of magnetic moment cluster (direction and size) inside microscopic magnetic domain; The stress field mainly causes the movement and rotation of the domain walls inside the ferromagnetic material, and further causes the change of magnetic moment cluster. Taking Q235 low carbon steel as an example, the effects of tensile stress σt on some important magnetic parameters of ferromagnetic materials under different excitation intensities (i.e., H0), such as the maximum value of applied magnetic field Hmax, intrinsic coercive field Hcj, hysteresis loss power per unit volume ph and anhysteretic magnetization Man, were obtained by setting macroscopic magneto-mechanical coupling test and fully considering the influence of demagnetizing field Hd (The standard ring specimen was used for demagnetization correction of the non-standard strip specimen). Meanwhile, the basic magnetization characteristics of ferromagnetic materials were discussed by introducing the basic magnetization curve F(H0, Ban) and considering the effect of σt as the equivalent stress field Hσ based on the theory of microscopic magnetic domain and the principle of thermodynamic. In the range of 635.4 A/m ≤ H0 ≤ 928.6 A/m and 0 MPa ≤ σt ≤ 350 MPa, the theoretical calculation models Man(H0, σt) and Hσ(H0, σt) in the magneto-mechanical coupling effect were obtained, which are in good agreement with the experimental results.