Effect of prior β processing on superplasticity of (α+β) thermo-mechanically treated Ti–632Si alloy

A new thermo-mechanical schedule involving processing in β and (α+β) phase fields for obtaining good superplastic properties in Ti–6.8Al–3.2Mo–1.8Zr–0.3Si alloy has been proposed and tested for optimum superplasticity. Superplastic behavior of the as-rolled and annealed sheets has been studied systematically in different temperature and strain rate ranges. It has been inferred that in addition to the grain size, prior to β processing and annealing in the (α+β) phase field also have a marked effect on superplasticity of the alloy sheets. As-rolled sheets in the (α+β) phase field having undergone annealing in β phase field after β rolling exhibit maximum superplastic elongation. Any further heat treatment of the as-rolled sheet reduces the extent of superplastic elongation.