The amplitude spectrum of the magnetoelastically induced voltage uB was studied during cyclic stressing of polycrystalline iron and nickel. Test specimens were loaded with a sinusoidically varying stress with a frequency of 25 Hz. The amplitude spectrum of voltage uB is a typical harmonic spectrum consisting of numerous harmonic components. The fundamental frequency of the spectrum was 25 Hz, the same as the loading frequency. The amplitude of the high frequency components of the spectrum increased in the beginning of stress cycling and decreased towards the fracture of the test specimen. This indicates that the cyclic plastic deformation has an effect on the micromagnetization of the material. An increase in the amplitude of the harmonics were observed even at stress amplitudes where no plastic deformation can be measured with an extensometer. The present results show that the magnetic measurements can be used to study the changes in the material microstructure and fatigue caused by cyclic stressing.
|Pages (from-to)||125 - 133|
|Number of pages||9|
|Journal||Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing|
|Publication status||Published - 1991|
|MoE publication type||A1 Journal article-refereed|