Nanoscale phase separation in an Fe70Nb10B 20 glass studied by advanced electron microscopy techniques

Abstract

Advanced techniques of electron microscopy were employed for analyzing a local structure of an as-formed Fe70Nb10B20 metallic glass. From nano-diffraction with an electron probe size of 1 nm, diffraction patterns of bcc-Fe and Fe-boride were observed which radicated an occurrence of nano scale phase separation in the glass. Atomic pair distribution function (PDF) analysis of the glass was also performed by means of precise electron diffraction intensity analysis taking advantage of energy-filter and imaging plate techniques. An atomic structure model was constructed using reverse Monte-Carlo calculation followed by Voronoi polyhedral analysis in order to know local atomic arrangements in the glass structure. The Voronoi analysis revealed atomic arrangements with bcc-Fe-like and B-centered trigonal prism polyhedral structures in this glass, which is consistent with the local structural study by nano-diffraction.