The Influence of Structure and Phase Composition of Titanium Alloy on Superplastic Deformation

Abstract

The paper presents research into the behavior of high-temperature plastic deformation of titanium alloy Ti–4.74 wt.% Al–5.57 wt.% Mo–5.04 wt.% V alloy (VT22) depending on its structure and phase composition. It is shown that the formation of fine-grain structure in this alloy is not a sufficient condition for realizing superplastic deformation. It is found that the formation of the ultra-fine grain structure in VT22 alloy leads to the temperature decrease down to 823 K at the beginning of plastic deformation. This allows achieving the percent elongation of the alloy specimens over 1300% within the temperature range of 973–1073 K and at a 6.9·10^–3 s^–1 initial tensile rate. The grain boundary sliding is considered to be the main deformation mechanism.