Oxygen-mediated high uniform plasticity in α-β titanium alloys
Yahui Yang, Xiuxia Wang, Biao Chen, Shenglu Lu, Kaiyue Liu, Shota Kariya, Xianzhe Shi, Xiaozhou Liao, Katsuyoshi Kondoh, Ma Qian, Jianghua Shen
Abstract
Titanium alloys are critically important materials, yet their development has long been constrained by a fundamental trade-off between yield strength and uniform elongation-a more challenging limitation than the conventional strength-ductility trade-off. Here, we present a dual strategy for α-β titanium alloys that transforms high oxygen from an embrittling liability into a powerful performance enabler. First, we leverage high oxygen ( ≥0.40%) to activate prominent pyramidal <c + a> slip in the α-phase. Second, we engineer a tailored α-β microstructure through alloy design (Ti-O-Fe), laser-based powder bed fusion, and annealing to enable sustained slip transfer across α-β interfaces. The resulting high-strength α-β alloys achieve record uniform elongations: Ti-0.45O-4Fe delivers ≥14% (total: ≥27%) at yield strengths ≥980 MPa, and Ti-0.5O-5Fe achieves ≥13% (total: ≥23%) at yield strengths ≥1075 MPa. This work simultaneously addresses the yield strength-uniform elongation trade-off and oxygen embrittlement, demonstrating a design paradigm for α-β titanium alloys.