Effects of stress on magnetically induced velocity changes for ultrasonic longitudinal waves in steels

Abstract

Effects of both uniaxial tensile and compressive stresses on the magnetically induced velocity changes for 10-MHz ultrasonic longitudinal waves were investigated in specimens of ASTM A-36, SAE 4340, and HY-80 steels. The magnetically induced ultrasonic velocity changes were found to exhibit characteristically different stress effects depending on the magnitude and sign, i.e., tensile or compressive, of the stress and the relative orientation between the stress and applied magnetic field . The effects of a compressive stress were particularly distinctive producing a prominent minimum in the velocity changes as a function of the applied magnetic field. The observed stress dependence of the magnetically induced velocity changes is qualitatively explained considering the effect of the stress and the magnetic field on the rotational motion of the domain magnetization caused by the propagating ultrasonic waves due to the magnetoelastic coupling.