Characterization of the microstructural, magnetic, and thermal properties of Fe-45Ni fabricated by laser powder bed fusion.

Fe–Ni alloys are binary alloys composed of iron and nickel in various proportions and are widely used in industry owing to their excellent magnetic properties, corrosion resistance, and thermal stability. Among the various Fe–Ni alloys, the Fe–45Ni alloy is suitable for applications requiring both thermal stability and strong magnetic properties. Therefore, this study investigates the effects on metallurgical, magnetic, and thermal properties of an Fe–45Ni alloy manufactured using laser power bed fusion (L-PBF). The microstructure of the sample manufactured under the process conditions with the highest relative density (99.28%) (laser power of 85 W and scan speed of 300 mm/s) was analyzed using electron backscatter diffraction, focusing on both the ZY and XY planes. For the magnetic properties, the permeability and coercivity along the Z- and Y-axes differed, with values of 60.77 × 10− 3 emu/(g∙Oe) and 20.93 Oe for the Z-axis, and 28.2 × 10− 3 emu/(g∙Oe) and 34.91 Oe for the Y-axis. For the thermal properties, the Fe–45Ni alloy had excellent thermal properties with a low thermal expansion coefficient of 6.0834 × 10− 6 and a Curie temperature of 414 ℃. The findings of this study suggest the feasibility of manufacturing Fe–45Ni soft magnetic components with stable thermal properties and high magnetic properties through Fe–45Ni alloy production via the L-PBF process.