Relationship between Structure, Phase Composition, and Physicomechanical Properties of Quenched Ti–Nb Alloys

Abstract

Transmission electron microscopy, X-ray diffraction analysis, and microindentation were used to study the changes in the structure, phase composition, elastic modulus, and hardness of the Ti–(9.6–34) at % Nb alloys after quenching in water from heating temperatures corresponding to the β region. The relationship between the physicomechanical properties (elastic modulus, microhardness) and the volume fraction of metastable phases detected in Ti–Nb alloys after quenching from the β region has been shown. It has been noted that the Ti–13.3 at % Nb alloy with a structure in which the ω phase with anomalous morphology in the form of massive plates is formed after quenching is characterized by maximum values of elastic modulus and microdurometric characteristics. The growth of the elastic modulus of the metastable β solid solution with increasing niobium content in alloys with a decrease in the average distance between the niobium–niobium atoms in the bcc structure has been justified. The possibility for calculating the elastic modulus of quenched Ti–Nb alloys based on the additive contributions of the elastic moduli of phases detected after quenching, which are proportional to their volume fractions has been considered.