Effect of internal stresses and dislocation features on the magnetic properties of soft ferromagnetic materials

This paper deals with the evolution of the magnetic anisotropy of non oriented 3%SiFe alloys plastically strained at various plastic strain levels (epsilon(p) = 0.5% / 3.6% / 9.8%). The magnetization characteristics have been investigated for a 50Hz sinusoidal magnetic field and under quasistatic excitation conditions (0.1Hz), along the direction of deformation and in the crossing corresponding direction (i.e. 0 degrees for the 90 degrees strained specimen and so on). Microstructural observations of the dislocation features for each sample are argued in this work. These experiments show that the magnetic properties markedly deteriorate when measurements are carried out in the direction of the applied stress. This phenomenon is less sensitive perpendicular to this applied stress. This plastically induced magnetic anisotropy remains quite constant whatever the plastic strain level. The influence of the kinematic stress level and the distribution of the dislocation features on magnetic properties is discussed.