On the correlation between magnetic domain and crystallographic grain orientation in grain oriented electrical steels

Abstract

The deviation angle of the easy magnetisation <001>-axes from the rolling direction (RD) strongly affects the magnetic domain configuration within individual grains and hence the overall magnetic properties in grain oriented electrical steels (GOES). In the current study, both angles of deviations; α: the angle between <001> and in-plane rolling direction, and β: the angle between <001> and out-plane rolling direction, where calculated using electron backscatter diffraction (EBSD) raw data to investigate the exact correlation between the crystal orientation and magnetic domain structure. Further, EBSD combined with forescatter detector (FSD) is used to reveal the magnetic domain configuration within individual oriented grains. The microstructure and microtexture of various GOESs with different chemical compositions and magnetic properties were characterised. The magnetic domain patterns were directly imaged and correlated to the crystal orientation and α and β deviation angles. It is demonstrated that the crystal orientation has a great impact on the magnetic domain patterns, width, and configurations. It was also shown that the grain boundary characteristics have a significant influence on the magnetic domain transfer between neighbouring grains. It was evident that low angle grain boundaries allowed domain transfer without a significant 2 change in the domain pattern, whereas high angle grain boundaries perturbed the magnetic domain pattern, width, and configuration. Furthermore, it was demonstrated that the size of the deviated orientation grains from ideal (110) <001> GOSS orientation is a critical microtexture parameter for the optimisation of magnetic property. Finally, it is concluded that the magnetic domain patterns and α and β angle of deviations are strongly correlated to the magnetic losses in GOES.

Correlations between Initial Goss Orientations with Different Deviation Angles and Evolution of Microstructure and Texture in Ultrathin Grain‐Oriented Silicon Steels

“…The deviation of the secondary grain from the exact Goss orientation was described by angles α (the angle between the <001> crystal axis of the secondary grain and the in‐plane rolling direction) and β (the angle between the <001> crystal axis of the secondary grain and the out‐plane rolling direction) in the other works. [ 3,14,15 ] That is to say, the ideal Goss texture had the <001> crystal axis parallel to the RD onto the rolling plane. In this work, all the four large selected initial grains had an exact Goss orientation; thus the included angle between the longitudinal direction (new RD) of the rectangular specimens and the initial RD of the raw material could be referred to as the deviation angle of the deviated Goss orientation.…”

Texture Intensity in Grain-Oriented Steel in the Main Stages of the Production Cycle

“…It should also be noted that the greatest accumulation of impurities occurred in this area, which resulted in the separation of non-metallic inclusions from the liquid in the first place, which served as a basis for the heterogeneous nucleation of equiaxed crystals with a random crystallographic orientation. Magnetic properties are highly dependent on the grain orientation and therefore the deviation of the 〈001〉 crystal axis from easy magnetization direction {100} [31]. Registered Barkhausen noises are generated by the movement of Bloch walls.…”

“…These results also indicate that the boundaries of the formed crystals make it difficult for Bloch walls to move, and consequently increase the magnetic hardness of the the material. Magnetic properties are highly dependent on the grain orientation and therefore the deviation of the ⟨001⟩ crystal axis from easy magnetization direction {100} [31]. Registered Barkhausen noises are generated by the movement of Bloch walls.…”

Magnetic Properties of Fe-Si Electrical Steel after Laser Scribing

“…Grain oriented electrical steel (GOEs) exhibit excellent magnetic properties longitudinally to their rolling direction, as a soft magnetic material are used mainly as a core for transformers [2][3][4]. The manufacturing of grain-oriented silicon steel require careful control of thermomechanical processing in order to generate desired microstructure and texture [5]. The processing steps and their parameters are adjusted to get at the end a Goss texture for excellent magnetization behavior and a large grain size with a sufficient number of movable domain walls [6].…”