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

Abstract

The deviation angle of the easy magnetisation 〈0 0 1〉-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 〈0 0 1〉 and in-plane rolling direction, and β: the angle between 〈0 0 1〉 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 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 (1 1 0) 〈0 0 1〉 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.