Structure Design of Soft Magnetic Materials Using Electron-Beam-Based Additive Manufacturing

Fe93.5Si6.5 (wt%) soft magnetic materials in toroidal shape are additively manufactured by means of electron beam powder bed fusion (PBF-EB). Different hatching strategies are applied to realize specific patterns of molten material alternating with non-molten powder particles. The specimens produced using different hatching strategies show identical relative densities but various structural features resulting in different magnetic properties. The magnetic performance of the specimens is characterized by determining hysteresis loops (B-H curves), power losses, and maximum magnetic flux density at frequencies between 50 and 1000 Hz. At constant mass, the different structures induced by using various hatching strategies have a strong influence on the hysteresis losses. These losses can be significantly reduced by applying a targeted structure design. The modified specimens show superior magnetic properties at sub-kHz compared to some soft magnetic materials fabricated by means of conventional methods and laser powder bed fusion (PBF-L).