Additive Manufacturing of Magnetostrictive Fe-Co Alloys

Fe-Co alloys are attracting attention as magnetostrictive materials for energy harvesting and sensor applications. This work investigated the magnetostriction characteristics and crystal structure of additive-manufactured Fe-Co alloys using directed energy deposition. The additive-manufactured Fe-Co parts tended to exhibit better magnetostrictive performance than the hot-rolled Fe-Co alloy. The anisotropy energy ΔK₁ for the Fe-Co bulk, prepared under a power of 300 W (referred to as bulk-300 W), was larger than for the rolled sample. For the bulk-300 W sample in a particular plane, the piezomagnetic constant d was large, irrespective of the direction of the magnetic field. Elongated voids that formed during additive manufacturing changed the magnetostrictive behavior in a direction perpendicular to these voids. Magnetic property measurements showed that the coercivity decreased. Since sensors should be highly responsive, Fe-Co three-dimensional parts produced via additive manufacturing can be applied as force sensors.