Effects of laser cutting on microstructure, hardness and magnetic properties of Fe-based amorphous ribbons

Abstract

Fe-based amorphous alloys are extensively utilized in electromagnetic components owing to their outstanding mechanical and magnetic properties, holding significant potential in solid-state transformers and amorphous motors. However, the deterioration of magnetic properties after processing has hindered the applications of these alloys. Traditional processing methods can induce deformation near the cutting edge and significant crystallization, severely degrading the magnetic property. In contrast, the laser cutting method offers minimal heat effects, a non-contact approach, and low magnetic property deterioration, making it as the optimal technique for cutting Fe-based amorphous alloys. In this research, a continuous-wave infrared laser cutting technique is employed to cut the amorphous ribbons into a ring shape at different laser powers and laminated magnetic cores should be prepared. The results reveal the presence of three distinct zones from the cutting edge to the substrate, namely the melted zone, heat affected zone and basis zone. Notably, Only the α-Fe(Si) phase is formed in the crystallization zone due to the relatively short duration of the laser cutting process for the amorphous ribbon and average grain sizes gradually decreases from the cutting edge to the basis zone. Furthermore, the amorphous-nanocrystalline dual-phase resulting from laser cutting exhibits a high hardness of approximately 1035 HV at 20 μm from the cut edge. Additionally, the laser-cut laminated cores at a power of 75 W exhibit excellent combined properties, including width of the crystallization zone of 80 μm and a low loss of 53.96 W/kg (200 mT, 100 kHz). This research offers a theoretical foundation for the industrialization of solid-state transformers and amorphous motors.