High-Strength Titanium-Based Alloy for Low-Temperature Superplastic Forming

Abstract

Reducing the deformation temperature is an important research task for superplastic forming of Ti-based alloys. This study demonstrates that the additions of Fe and B significantly improve microstructural homogeneity and superplastic performance, increase the post-forming mechanical strength, and reduce the superplastic deformation temperature of a Ti-Al-Mo-V alloy. The designed alloy exhibits an excellent superplastic deformation behavior with elongation of 590 to 1050 pct at 675 °C to 775 °C with a constant strain rate in a range of 5 × 10−4 to 5 × 10−3 s−1, and a high room temperature yield strength of 1020 MPa, a UTS of 1080 MPa, and elongation-to-failure of about 6 pct both after annealing and after superplastic deformation with a strain of 0.69 at 775 °C. The microstructure and the strain-induced changes in the size and shape of grains are discussed. The modification of the β-phase morphology leads to an increase in the curvature of interphase boundaries in the modified alloy. Advanced superplasticity and improved mechanical properties make the studied alloy a very attractive material for complex parts in numerous advanced applications.