Stress dependence of sound velocity in Fe-based amorphous wires

The dependence of the longitudinal sound velocity on the bias magnetic fiel d and tensile stress in Fe77.5Si7.5B15 amorphous wires are presented, The m easurements were made using the magnetostrictive delay line principle. The results show that changes in longitudinal sound velocity with bias magnetic held and tensile stress applied along the length of amorphous wires are st rongly dependent on the thermal treatment. In the as-cast state, the change of the longitudinal sound velocity is negligible. There is a monotonic dep endence of the sound velocity value on the tensile stress up to about 12 MP a. For about 16 MPa and 600 A/m tensile stress and bias magnetic field magn itude, respectively the saturation value of the longitudinal sound velocity is reached.