Excellent strength-ductility balance of a titanium alloy via controlling stress-induced ω transformation assisted by α-β hybrid structure

A Review of Deformation Mechanisms, Compositional Design, and Development of Titanium Alloys with Transformation-Induced Plasticity and Twinning-Induced Plasticity Effects

“…Different deformation modes, such as stress-induced phase transformation (including stress-induced body-centered cubic (bcc) β-to-hexagonal close-packed (hcp) α ′ martensitic transformation [8,[19][20][21][22], stress-induced β-to-orthorhombic α ′′ martensitic transformation [23][24][25][26][27], and stress-induced β-to-ω phase transformation [28][29][30][31]), deformation twinning [7,13,14,[32][33][34], and dislocation slipping [35,36], can be activated in Ti alloys accommodating increased β phase stability. As schematically depicted in Figure 1, the deformation of traditional high-strength Ti alloys is dominated by dislocation slipping owing to the high β phase stability, leading to a high yield strength but low uniform elongation and limited strain hardening [13].…”

“…A subclass of TRIP Ti alloys has been developed based on stress-induced β-to-ω phase transformation. This class of TRIP Ti alloys demonstrates an excellent combination of mechanical properties, like Ti-9Cr-0.2O [28,100] and Ti-6Mo-3.5Cr-1Zr [29,58]. By introducing stress-induced plate-shaped ω phase transformation to replace the stress-induced β-to-α ′′ transformation, it becomes possible to overcome the low yield strength of the traditional TRIP/TWIP Ti alloys.…”