Enhancement of magnetostriction in laser powder bed fusion Fe-Ga alloy by texture formation

Magnetostrictive Fe–Ga alloys have received much attention in sensing and harvesting applications owing to their outstanding mechanical and magnetostrictive properties. The largest magnetostriction in Fe–Ga is found along the <100> direction. Utilising additive manufacturing (AM) for preparation of Fe–Ga will expand the potential to manufacture complex shapes and geometries, if the strong <100> texture is formed. This study investigated the saturation magnetostriction of a polycrystalline Fe–Ga alloy prepared by laser powder bed fusion (L-PBF) under controlled processing parameters. The results revealed that the combination of a narrow hatch space and laser remelting treatment significantly enhances the apparent magnetostriction of the L-PBF Fe–Ga alloy. Notably, at a hatch space of 40 μm, the highest saturation magnetostriction is around 70 ppm. This value is almost three times higher than that of a polycrystalline Fe–Ga alloy with the same chemical composition where grains are randomly oriented.