Synergistically Improving the Strength-Impact Toughness in Dual-Phase Titanium Alloy via Martensite-Engineered α+α^′+β Microstructure

Titanium alloys exhibit low-temperature brittleness. A major challenge in their use has always been enhancing their impact toughness without compromising their strength. In this study, a dual-phase titanium alloy with α+ α′+ β phases was designed through alloying with Fe element, and its microstructure was carefully adjusted via heat treatment. The impact failure mechanism was analyzed through characterization in conjunction with molecular dynamics calculations. The designed Ti-6Al-2.5V-2Fe titanium alloy demonstrated a tensile strength of ∼1100 MPa, an elongation at break of ∼22 %, a room temperature impact toughness of ∼71.2 J/cm², and a low-temperature impact toughness of ∼54 J/cm², respectively. Compared to reported titanium alloys, it exhibits an excellent synergistic combination of strength and impact toughness, as well as good low-temperature impact toughness. These outstanding properties highlight its great potential for applications across both room and low-temperature environments.