Low temperature superplasticity through grain refinement in Ti-6Al-4V by a novel route of quench-roll-recrystallise

A ‘quench + roll + recrystallise’ method was simulated through compression testing of initially ‘water quenched’ Ti-6Al-4V alloy at a temperature of 973 K and rolling strain-rate 100 s−1 in order to achieve superplasticity at lower temperature through grain refinement, with a view to increase die life. Subsequent annealing of wire-cut specimens of a rolled sheet at temperatures 1023, 1073, 1123, and 1173 K revealed that, the structures became finer and equi-axial in the range of 1–2 μm, when annealed at 1073 and 1123 K. In compliance to this behavior, a tensile sample from industrially ‘quenched + rolled’ sheet at 973 K could produce an elongation of 740% at a temperature of 1073 K under a strain-rate of 10−3 s−1. Significant elongation of 652% was obtained at further lower temperature of 1023 K under a strain-rate of 10−3 s−1. Quench-roll-recrystallise technique pushes down superplastic forming temperature to 1023 K.