Effect of Cold Drawing and Annealing in Thermomechanical Treatment Route on the Microstructure and Functional Properties of Superelastic Ti-Zr-Nb Alloy

In this study, a superelastic Ti-18Zr-15Nb (at. %) alloy was subjected to thermomechanical treatment, including cold rotary forging, intermediate annealing, drawing, post-deformation and additional low-temperature aging. As result of two structures β-phase were obtained: fine-grained structure (d ≈ 3 µm) coarse-grained 11 µm). Cold drawing promotes grain elongation in the direction; state, grains form with size 4 × 2 µm, they grow 16 6 µm. Post-deformation annealing (PDA) at 550 °C for 30 min leads sizes 5 µm respectively. After PDA (30 min) wire exhibits high tensile strength (UTS = 624 MPa), highest failure (δ ≥ 8%), maximum difference between dislocation transformation yield stresses, as well recovery strain (εrSE 3.3%) total elastic + (εrel+SE 5.4%). Additional aging 300 30–180 ω-phase formation, hardening, embrittlement, significant decrease strain.