Evolution of α phase in metastable β titanium alloys studied by small-angle X-ray scattering

Abstract

Small-angle X-ray scattering (SAXS) is a technique which makes use of elastic scattering of X-ray radiation on inhomogeneities in electron density in the studied material In particular, a difference in chemical compositions between individual phases can be detected. In this research, SAXS was used to study the evolution of α particles in aged samples of a metastable β titanium alloy, Ti-6.8Mo-4.5Fe-1.5Al (LCB). In order to obtain scattering patterns for a known crystallographic orientation, the experiments were carried out on single crystals grown by a floating zone technique. Aged single-crystalline samples were measured in three different orientations, namely (001), (110) and (111) planes of the bcc β matrix oriented perpendicularly to the primary beam. Resulting scattering patterns exhibited symmetries which correlated with the orientation of the studied sample. A simple theoretical model was developed to interpret the shape and orientation of the observed scattering streaks. Good qualitative agreement between experimental data and simulation was found and the first results of the model are presented in this paper.