Microstructure and properties of Ti-Al-Sn-Zr-Mo-Nb-Ta-W-Si cast high-temperature titanium alloy

A series of Ti-Al-Sn-Zr-Mo-Nb-Ta-W-Si high-temperature titanium alloy samples were designed and prepared with different Mo eq by a vacuum induction suspension melting furnace. The fluidity property, microstructure, and mechanical properties were investigated. Results show that the microstructures are composed of Widmanstätten structures, and the width of α-laths decreases from 2.85 µm to 1.43 µm as the addition of Mo eq increases from 0.86 to 4.48. It is also observed that with the increase of Mo eq , the strength of the alloy increases at room temperature and decreases at 650 °C. Ti-5.76Al-2.30Sn-5.91Zr-3.10Mo-2.94Nb-1.16Ta-0.23Si alloy with the Mo eq of 4.16 exhibits a good combination of fluidity and mechanical properties at both room temperature and 650 °C, which is attributed to its minimum viscosity and maximum work hardening rate. This alloy can be considered a candidate material for casting high-temperature titanium alloys.