Micromagnetic measurement for characterization of ferromagnetic materials’ microstructural properties

Abstract

Magnetic Barkhausen noise (MBN) is measured in low carbon steels and the relationship between carbon content and parameter extracted from MBN signal has been investigated. The parameter is extracted experimentally by fitting the original profiles with two Gaussian curves. The gap between two peaks (ΔG) of fitted Gaussian curves shows a better linear relationship with carbon contents of samples in the experiment. The result has been validated with simulation by Monte Carlo method. To ensure the sensitivity of measurement, advanced multi-objective optimization algorithm Non-dominant sorting genetic algorithm III (NSGA III) has been used to fulfill the optimization of the magnetic core of sensor.

Evaluation of Plastic Deformation in Steels with Magnetic and Acoustic Techniques

“…Due to the increasing degree of interactions between the MDW and the dislocations when increasing the plastic deformation, the magnetizing force is not big enough to release them and reduces the movement of the MDW, decreasing the MBN. On the other hand there is also a greater hardening of the material as the deformation increases [14,15].…”

“…In general, it is assumed that a greater number of defects increases the activity of the MBN, since there will be more sudden movements of the MDW. However, if these defects act as strong pinning sites, they prevent the movement of MDW, and thus the activity of the MBN will decrease [15].…”

“…The decrease in the number of peaks and their transformation into a central peak could be due to the fact that the MBN signals are generated mainly by processes connected with the rapid reorganization of the structure of the MDW, due to the creation and annihilation of the domains. As the deformation progresses, movement speed of the MDW, which means that their presence would decrease the MBN [15,16].…”

“…This fact is explained in the following way: As the plastic deformation increases, the dislocation density increases together with an increase in dislocations interaction with MDW. The interaction between the walls of the domains and the dislocations seems to be stronger for MDW of at 180°, than for MDW at 90° [13][14][15][16][17][18][19].…”

Design of advanced micro-magnetic sensors for various applications

“…Therefore, the rapid and non-destructive testing methods for mechanical properties is helpful for the comprehensive evaluation of parts. Many scholars have pointed out that the microstructure and macroscopic material properties (mechanical properties, electromagnetic properties, etc) are difference in materials [4,5]. As an important method, micro-magnetic detection is based on the theory of micro-magnetism and uses the hysteresis model to establish the relationship between mechanical properties, magnetic properties and the microstructure of materials [6][7][8][9].…”