Magnetomechanical Effect in Iron and Nickel Polycrystals During Cyclic Loading
Date
Authors
Major Professor
Advisor
Committee Member
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
When ferromagnetic material is loaded a voltage is induced in the induction coil around the loaded material. This induction is caused by the magnetomechanical effect /1/. The stress makes the internal magnetization change and the changes take place by the movement of domain walls or by the rotation of domain magnetization vectors. This interaction has been investigated in details by Jiles et al /2/. The domain wall distribution and thus the changes in magnetization during loading is a function of external magnetic field. The movements of domain walls is influenced also by the microstructure of the material. A clear interaction between domain walls and dislocations has reported by Astie et al /3/. Consequently the changes in the dislocation structure will cause changes in the induced voltage. This interaction can be utilized to study the straining processes during cyclic loading and fatigue of ferromagnetic metal /4/, /5/. The present results show that the fatigue process of ferromagnetic material can be measured nondestructively by this techinque and also that it is possible to estimate the fatigue life of material under loading.