Local Atomic Structures of Amorphous Fe₈₀B₂₀ and Fe₇₀Nb₁₀B₂₀ Alloys Studied by Electron Diffraction

Abstract

Effect of Nb addition on the stabilization of amorphous Fe₈₀B₂₀ alloy was studied by electron diffraction structure analysis with the help of computer simulation. Atomic structure models with dense-random-packing 5000 atoms were constructed to reproduce interference functions obtained experimentally for the amorphous Fe₈₀B₂₀ and Fe₇₀Nb₁₀B₂₀ alloys. In the structure models so obtained, prism-type local atomic arrangements dominated around B atoms in both the alloys, while deformed-bcc and icosahedral-like clusters were frequently found around Fe atoms. The icosahedral-like clusters and short Fe–Fe bondings were more frequently found in Fe₇₀Nb₁₀B₂₀. The difference of glass forming abilities of these alloys is discussed in relation to the local structural differences.