A low coercivity, high Si content, directed energy deposited Fe-6%Si electrical steel

Artikel i vetenskaplig tidskrift, 2025

Increasing the Si content in Fe-Si alloys increases the resistivity and decreases eddy current losses. While conventional processing of high Si content Fe-Si alloys is challenging, additive manufacturing has been demonstrated as a viable alternative. However, it has been quite challenging to understand the nature of chemical ordering (B2/D03 type) in these AM processed alloys, and its consequent influence on the coercivity (Hc) and saturation magnetization (Ms). Hence, in this work, a Fe-6 wt% Si alloy was prepared by laser directed energy deposition (DED) using different laser fluences (energy densities). The presence of body centered cubic (BCC) grains with B2 and D03 type chemical ordering in the as-deposited condition, was conclusively established by coupling synchrotron-based x-ray diffraction and transmission electron microscopy investigations. While laser fluence significantly influenced BCC grain size and texture, the resulting alloy exhibited exceptional soft magnetic properties, achieving a Ms value of 201 emu/g and a low Hc of 1.1 Oe. Post-deposition heat treatment further reduced the Hc value to ∼0.8 Oe, rendering this DED processed Fe-6wt% Si alloy highly suitable for engineering applications.