Small-Angle Neutron Scattering Study on Fe–Cu–Nb–Si–B Nanocrystalline Alloys

Abstract

Small-angle neutron scattering (SANS) from Fe–Cu–Nb–Si–B nanocrystalline alloys has been measured in a magnetic field. Significant differences between nuclear and magnetic scattering profiles have been observed. Most of the magnetic scattering profiles take an asymptotic form of I(q)∼q⁻³ in a high-q region, which indicates that the distribution of local magnetization is not uniform in a BCC-Fe grain. All the nuclear scattering profiles, on the other hand, take an asymptotic form of I(q)∼q⁻², which implies that the concentration fluctuation of the Ornstein-Zernike type exists in nanocrystalline alloys. However, no such fluctuation is observed in Fe–Cu–Si–B and Fe–Nb–Si–B alloys which do not have any nanocrystalline structures. These results suggest that the concentration fluctuation of the Ornstein-Zernike type seems to be closely related to the nanocrystalline microstructures.