Thermal Stability and Mechanical Properties of Low-Activation Single-Phase Ti-V-Ta Medium Entropy Alloys

A series of titanium-vanadium-tantalum (Ti-V-Ta) medium entropy alloys have been fabricated with all of them exhibiting a single-phase body-centered cubic structure in the homogenized states, and their thermal stability as well as their mechanical properties have been investigated. Among the four studied alloys, Ti27V33Ta40, Ti33V33Ta34, Ti40V33Ta27, and Ti45V20Ta35, the equi-atomic Ti33V33Ta34 has shown the highest thermal stability, without secondary phases formed after annealed at 400–700°C for 48 h, while decompositions have been observed in the other three alloys. All the four alloys have exhibited a good compression strength of 394–527 MPa at 800°C, while, except Ti27V33Ta40, maintaining an acceptable tensile ductility with fracture strains of 7.6–13% at room temperature. Furthermore, the low neutron activity of the Ti-V-Ta alloys grant them application potentials in nuclear engineering.