Overcoming the strength-ductility trade-off in <b>ω</b> -phase strengthened metastable <b>β</b> titanium alloys via dual heterogeneous structure

This study successfully developed a dual heterogeneous structure metastable β titanium alloy via partial recrystallization and low-temperature aging. Compared to ω-phase strengthened homogeneous coarse-grained structures, dual heterogeneous structure demonstrated an exceptional balance between yield strength and ductility. Notably, the Ti-Nb alloy achieved a yield strength surpassing 1 GPa while retaining approximately 5% ductility. The enhancement in yield strength was attributed to multiple strengthening mechanisms, including ω-phase precipitation and hetero-deformation-induced (HDI) strengthening. Moreover, the synergistic effects of HDI hardening and TRIP/ TWIP effects mitigated the embrittling impact caused by the large amount of ω-phase, while also enhancing strain hardening capacity.