Mechanical properties and deformation mechanism of a novel metastable β-type Ti–4V–2Mo–2Fe alloy

Herein, a β-type titanium alloy Ti–4V–2Mo–2Fe (at. %) with excellent mechanical properties was designed using the molybdenum equivalence approach combined with the Bo‒Md map. Alloy design exhibited some noteworthy mechanical characteristics, including a uniform elongation of 31%, high yield strength of 736 MPa, and stable intervals with high work-hardening rates. A systematic investigates of the deformation mechanisms reveals that twinning-induced plasticity (TWIP) effects cause the formation of complex twinning networks in the alloy and increase plasticity. Both early and middle stages, the alloy's work-hardening behavior is dominated by the dynamic Hall-Petch effect, whereas the late work-hardening behavior of the alloy is dominated by the dislocation slips. Simultaneously, a small ω phase forms during the deformation, promoting the work-hardening ability of alloys.