THE BEHAVIOURS OF ELASTIC MODULUS AND ULTRASONIC ATTENUATION IN NdFeB MAGNET

The elastic modulus and attenuation coefficient of polycrystalline NdFeB magnet have been measured at different temperatures by ultrasonic method. At room temperature, the elastic modulus shows small but apparent anisotropy, while at low temperatures the ultrasonic velocity and attenuation coefficient are both changed anomalously. We suppose that this phenomenon is caused by the abrupt change of the direction of magnetization.