Submicrostructure and Characteristics of the Short-Range Atomic Order in an Amorphous Ti–Ni–Ta–Zr-Based Surface Alloy Formed on a TiNi Substrate by the Electron-Beam Method

Abstract

This study presents the results of studying the microstructure and topological short-range atomic order in an amorphous Ti−Ni−Тa−Zr-based surface alloy formed by the additive method through pulsed electron-beam liquid-phase mixing of the “Ti70Ta30 film (50 nm)/Zr film (100 nm)/TiNi substrate” system. It is shown that an amorphous structure with a thickness of 2 μm is formed in the cross-section of the surface alloy and is characterized by the gradient chemical composition. It is found that the transition sublayer adjacent to the TiNi substrate has a nanocomposite crystalline structure based on the Ti2Ni intermetallic compound. By means of the atomic radial distribution function method, using electron nanobeam diffraction data, a study of the topological short-range atomic order in the amorphous layer is performed. It is shown that the atomic structure in the amorphous surface Ti−Ni−Тa−Zr alloy has a cluster structure which can be described by the superposition of coordination polyhedra interconnected with each other by common faces corresponding to the different crystalline devitrification phases.