Achieving outstanding strength-toughness matching in β titanium alloy with coherent αs/β interface triangular αs and fine dispersed αs phases

Achieving strength-toughness trade-off in β titanium is a significant challenge, which are typically incompatible properties. In this study, high-strength toughness synergies can be achieved by adding an appropriate amount of Nb element alloy and conducting appropriate heat treatment to obtain coherent α s /β interface triangular α s and fine dispersed α s phases. The undeformed Ti-4.3Al-6.5Mo-3V-2Sn-2Zr-5Nb sample exhibits a tensile strength of 1298.5 MPa and a toughness of 76.2 MPa·m 1/2 , surpassing many deformed titanium alloys. The coherent α s /β interface triangular α s and fine dispersed α s phases with good strain compatibility effectively combine the mechanisms of dispersed precipitation strengthening and coherent interface strengthening, resulting in excellent strength toughness matching of titanium alloys. The α s phases with coherent α s /β interface activate the pyramidal <c + a> slip systems, which can enhance toughness. These findings provide a crucial theoretical and practical foundations for the development of complex castings with excellent mechanical properties.