Effect of Rapid Solidification on Magnetostriction and Microstructure in Melt-Spun Fe-Al Ribbons

In this paper, we report magnetostriction measurements and an investigation of structural properties on melt-spun ribbons of Fe_85.7Al_14.3, Fe_81.3Al_18.7, and Fe_77.7Al_22.3 ribbons produced at different wheel speeds. The bcc-disordered A2 structure is obtained for 14.3 and 18.7 at %Al whereas the alloy with 22.3 at %Al exhibits the DO₃-type structure. With increasing Al concentration, the saturation magnetization decreases, whereas the average lattice constant, longitudinal, transverse, and volume magnetostriction increase. However for each alloy, the crystallite size, lattice constant, and magnetostriction vary randomly with wheel velocity. While the behavior of the longitudinal magnetostriction versus applied field is similar for all samples, the behavior of the transverse magnetostriction is strongly dependent on the wheel speed. These results indicate that the formed structural disorder and the stresses in the ribbons are different with wheel speed.