Nanocrystallization Of Fe-base Amorphous Soft Magneticalloy By Scanning Irradiation With Yb-doped Fiber Laser

Fe-based nanocrystalline alloys Fe_73.5Cu₁Nb₃Si_13.5B₉have been widely applied tomagnetic components in electrical and electronic fields because they have superiorsoft magnetic properties, like low coercivity, low high frequency losses, highsaturation flux density, high initial permeability, good thermal stability and low cost.Traditional heat treatment has been achieved industrialization, but there are manydefects in the traditional annealing， which include long time, high energyconsumption and high scrap rate of mass and so on. Laser is a high-intensity heatsource. Laser power is accurate and controllable, which can realizeconstituency irradiation. Nanocrystallization process of Fe-based amorphous softmagnetic materials can be precisely controlled laser with photothermolysis of laser.Compared with the CO2laser, Yb-doped fiber laser has more short wave length, andhigh absorption rate for metal. Fiber laser is increasingly compact and high integrated,which provides possibility of efficient preparation of iron-based nanocrystalline softmagnetic by fiber laser.The paper presents the laser irradiation method for rapidly fabricating Fe-basednanocrystalline. The sample which included the annular cores with internal diameterof14mm and external diameter of19mm and original amorphous ribbons with20μm-thick and3.2mm-wide are irradiated by Yb-doped fiber laser in different laserpower and laser power. X-ray diffraction and transmission electron microscopy （TEM）are used for microstructure analysis and observation. After irradiated by theappropriate condition, the annular cores have low coercivity （≤1A/m） and highinitial permeability. For the original amorphous ribbons, after irradiated by theappropriate condition, the coercivity gets smaller. However, the initial permeabilityhas no change due to the limit of the irradiation time. Experiments show thatirradiation with Yb-doped fiber laser is an effective and feasible method forproduction of Fe-based nanocrystallized alloys, which can avoid the abuse oftraditional annealing, and the uniformity of the laser beam and the irradiation time hasgreat influence on the soft magnetic properties of the samples.