A Study of Stress – Induced Subtle Magnetic Changes in a Mild Steel using Barkhausen Emission-Aided Analysis Approaches

In this study magnetic Barkhausen emission – based approaches were used to reveal and characterize some interesting elastic stress - induced quantitative and qualitative subtle changes in the micromagnetic activity of steels. The quantitative changes consist in a multiplication of domain walls whereas the qualitative in the formation of two major modes of domain wall motion. Concerning the first kind of changes, it was shown that the experimentally obtained low limit of elastic stress at which such micromagnetic changes may occur is in reasonable agreement with existing theoretical as well as experimental results. Concerning the second kind of changes, it was shown by means of two types of distribution approach, that these two modes of wall motion may be related to the grain boundaries as well as the grain interior micromagnetic activity. In this context, it was also shown that an increase in the supplied elastic strain leads to a broadening of both distribution modes.