Directional growth effect on magneto-mechanical properties of Fe81Al19 alloy

Abstract

Directional growth effect on magneto-mechanical properties of Fe81Al19 alloy is studied. The ideal model of heat flux for directional solidification (DS) technique is proposed, and the tuned A/L (the ratio of cross-sectional area and length for the ingot) and ΔT (temperature difference) are adopted to increase heat flux (q). The experimental result shows that the increase of q effectively promotes the degree of (011)[100] Goss texture and therefore helps to form an oriented stripe domain structure. Large λ100 of 93.8 ppm attained for this optimized Fe81Al19 alloy prepared by DS method is very close to that of the Fe81Al19 single crystal (95.0 ppm). For the optimized DS prepared Fe81Al19 alloy, high magnetostriction sensitivity (dλ/dH) of 0.45 ppm/Oe leads to huge ΔEs/E0 of ∼10% and attractive ΔE/E0 of 8.2% at small H = 0.25 kOe. The above remarkable magneto-mechanical properties, low cost of Fe81Al19, and simple process of DS favor for applications. This work proposes an ideal model to emphasize the importance of heat flux in DS, and experimentally attains the remarkable magneto-mechanical properties for Fe81Al19 alloy prepared by DS.