On the role of crystal and stress anisotropy in magnetic Barkhausen noise
The article describes the micromagnetic behavior of non- and pre-plastically deformed high strength steel samples under applied stress using different magnetic nondestructive methods such as magnetic Barkhausen noise analysis and hysteresis measurements. It was found that the maximum amplitude of Barkhausen noise (Mmax) increases with applied stress up to a certain point and then decreases again (so-called Mmax(sigma)-curve). Changes of magnetostriction, hysteresis curves and magnetic domain structures have been measured and have been further investigated to find out the reasons with respect to macro- and microscopic material behavior. The results obtained are mainly discussed on the basis of the Villari effect and the relation between applied stress and the Barkhausen noise parameters is described. It is concluded that the interaction between crystal and stress anisotropy is the main reason of the specific Mmax(sigma)-curve observed.