Title :
AC magnetic field frequency dependence of magnetoacoustic emission
Author :
Namkung, M. ; Wincheski, B. ; Fulton, J.P. ; DeNale, R.
Author_Institution :
NASA Langley Res. Center, Hampton, VA, USA
Abstract :
It has previously been proved that there is a strong correlation between the low-frequency AC applied magnetic field amplitude dependence of the asymmetry of the magnetoacoustic emission (MAE) burst and the strength of the domain-wall-defect interaction in iron-base ferromagnets. The AC magnetic field frequency dependence of the asymmetry is investigated in the range of 1 to 200 Hz. When represented by the third moment of the rectified acoustic emission pulses, the asymmetry becomes a bell-shaped function of frequency with its center located around 25 Hz. The experiment is performed with low-carbon, high-yield stress steel specimens of three different levels of domain-wall-defect interaction strength. The results show that the increase in the interaction strength causes a vertical down shift of the asymmetry in the entire frequency range investigated
Keywords :
acoustic emission testing; carbon steel; ferromagnetic properties of substances; magnetic domain walls; magnetoacoustic effects; 1 to 200 Hz; AC magnetic field; asymmetry; bell-shaped function; domain-wall-defect interaction; ferromagnets; frequency dependence; high-yield stress steel specimens; low-carbon steel; magnetoacoustic emission; quantitative NDE; rectified acoustic emission pulses; third moment; Casting; Frequency dependence; Grain boundaries; Magnetic domain walls; Magnetic domains; Magnetic fields; Magnetic hysteresis; Magnetic materials; Steel; Stress;
Conference_Titel :
Ultrasonics Symposium, 1992. Proceedings., IEEE 1992
Conference_Location :
Tucson, AZ
Print_ISBN :
0-7803-0562-0
DOI :
10.1109/ULTSYM.1992.275860
