Nanocrystallization and magnetic property improvement of Fe78Si9B13 amorphous alloys induced by magnetic field assisted nanosecond pulsed laser

Abstract

The influence of the magnetic field (514 and 1642 Gauss) assisted nanosecond pulsed laser processing on the structure and magnetic property of Fe78Si9B13 amorphous alloy is analyzed in this paper. The magnetic field causes the surface to splash obviously, which is related to the Lorentz force generated by the applied magnetic field and current. The magnetic field assisted nanosecond pulsed laser does not cause the Fe78Si9B13 amorphous alloy to crystallize significantly, and the XRD pattern still shows a typical amorphous diffuse scattering peak. However, the magnetic field can enhance the crystallization sensitivity of the Fe78Si9B13 amorphous alloy, and make more nanocrystals formed in the heat affected zone based on the SAXS and TEM data. Moreover, the magnetic property of the Fe78Si9B13 amorphous alloy is improved when the magnetic field is 514 Gauss. The main reason is that the transition from fcc structure units to bcc structure units occurs in the amorphous alloy. When the applied magnetic field intensity is larger (1642 Gauss), the saturation magnetization decreases. It can be explained by the B content in the residual amorphous matrix is too high with the precipitation of α-Fe(Si) nanocrystals, which is not conducive to the increase of the saturation magnetization.