Increasing cold workability of Ti-6Al-4V alloy via thermo-mechanical processing: simulation and experiment

Abstract

Rolling temperature is thought to have a significant effect on the cold workability of Ti-6Al-4V alloy. To investigate the extent of this effect, four Ti-6Al-4V strips were hot rolled at different rolling temperatures in the range of 650–950 °C while other process parameters were invariant. The specimens revealed an increase in work hardening capacity with increase in rolling temperature, based on tensile and plane strain compression testing. After 10 % cold rolling, the same annealed samples exhibited propagation of edge cracks in specimens that had been hot rolled at 650, 750 and 850 °C while no cold rolling defect was found in the specimen hot rolled at 950 °C. The results of finite element method reveal that during cold rolling, the von Mises stress field is decreased as a result of increasing previous hot rolling temperature. In accordance with X-ray diffraction results, increasing previous hot rolling temperature is associated with lower lattice strain storage during subsequent cold rolling.