Magneto-mechanical properties of Fe100-xAlx alloys (x = 14-27) prepared by directional solidification

Abstract

The magneto-mechanical properties, including ΔE and damping capacity, magnetic properties, magnetostriction, and phase constitutions of Fe100-xAlx alloys, prepared by directional solidification (DS) are systematically studied. The remarkable ΔE effect of 10.1%, magnetostriction (Δλ) of 141 ppm, dλ///dH of 0.43 ppm/Oe, magneto-mechanical coupling (K) of 48%, and damping capacity of 6.0% reached for Fe81Al19 alloy favor for applications. The increased Δλ with increasing x from 14 to 19, possibly related to increased amount of Al-Al pairs, largely improves dλ///dH and therefore ΔE and damping capacity. Nevertheless, the formation and growth of D03 phase for higher Al content (x = 23-27) results in the reduced Δλ and dλ///dH, and therefore K, ΔE effect, and damping capacity. The proportional relation between ΔEs/E0 and K2 suggests that the experimentally ΔEs/E0 is consistent with theoretically calculated K2. Additionally, the proportional relation between the experimentally measured ζ and theoretically estimated (ΔW/W)eth suggests the change of damping capacity with H is mainly governed by the micro eddy-current mechanism resulted from magnetic domain wall motion. Most importantly, the experimental result suggests a cost-effective method to attain remarkable magneto-mechanical properties for Fe81Al19 alloy.