A review of microstructure and texture evolution during plastic deformation and heat treatment of β-Ti alloys

Abstract

In the present work, microstructure and texture evolution during plastic deformation and annealing treatment of near beta (β), meta-stable β, and stable β-Ti alloys are reviewed. The evolution of microstructural features such as shear bands (SBs), martensite (α″/α′), dislocations and precipitation (omega (ω), and alpha (α) phases) during plastic deformations significantly influence the mechanical properties. Further, the microstructure and texture evolution in the deformed β-Ti alloys also depend on the deformation process like rolling, extrusion, and/or severe plastic deformation (SPD). The formation of α-fiber (RD// <110>) and γ-fiber (ND// <111>) are typically observed in cold-rolled and recrystallized β-Ti alloys. However, the fiber texture intensities or the volume fraction of these fibers and other texture components (Cube (100) <001>, Rotated Cube (100) <011>, Goss (110) <001> and others) varies from process to process. Dynamic recrystallization (DRX) and dynamic recovery (DRV) are influenced mainly by the imposed strain rate, activated deformation modes, and deformation temperature in β-Ti alloys. In general, the activation of deformation mechanisms viz. slipping, twinning, kinking, and SBs formation are primarily dependent on the reduction ratio and the composition of the β-Ti alloys. The formation of SBs and deformation twins contributes to the ductility of the β-Ti alloy sheets for structural/automotive applications. Moreover, the presence of α″/α′ and ω-phase showed an improvement in the strength of β-Ti alloys. β-Ti alloys such as Ti-Nb alloys are known for their acceptable biocompatibility and low young’s modulus (E, 40–65 GPa). However, the formation of α′/α″ during plastic deformation leads to lowering of E.