Examining the correlation between microstructure and Barkhausen noise activity for ferromagnetic materials

Barkhausen noise emission studies have been used to detect microstructural variations and to measure residual stresses in ferromagnetic materials. The stresses generated due to mechanical wear and tear, abrasion and prolonged service exposure may also lead to phase changes within the material. Presence of residual stresses and phase changes can cause damage to the structural parts and should be prevented. It is therefore important to be able to detect these phase changes in order to take action to mitigate structural failures. Phase changes are associated with evolution of material properties and need to be monitored. This study is based on utilizing Barkhausen noise emission analysis as a method for characterizing the microstructure of the material under examination and in turn monitoring the phase changes within the material. Steel samples in which microstructural changes are produced by the transformation of high temperature austenitic phase have been examined.