High magnetostriction of the polycrystalline alloy (Fe0.8Al0.2)97B3

In the present work we investigate the alloys (Fe0.8Al0.2)100−xBx, for x > 2.0 up to x = 5.0. A maximum of the total magnetostriction was found for the alloy (Fe0.80Al0.20)97B3. In this sample we measured the boron contents using WDS and we did not find boron in the matrix, while the precipitates formed after annealing of as cast samples are essentially the phase Fe2B. By a detailed XRD study of this sample using Mo Kα radiation, the presence of the phases Fe3Al (D03) and α (A2) was determined. The coexistence of both phases was determined to be the origin of the increase of the magnetostriction of this material. The value of λlong = 80 × 10−6 achieved in the as cast sample with x = 3 indicates that the introduction of texturing to the material should provide even higher enhancement of the magnetostriction. In addition to high magnetostriction values, the alloy can be machined, welded and is also a low cost material, therefore the alloy (Fe0.80Al0.20)97B3 reveals a great promise as a material to be used on sensors and actuators assembly.