Precipitation-hardened refractoryTi-Nb-Hf-Al-Ta high-entropy alloys. Issue 1 (January 2021) - Panina, E
Abstract: This study reports the structure and mechanical properties of new refractory Ti37.5 Nb12.5 Hf25 Al25, Ti40 Nb30 Hf15 Al15, and Ti40 Nb20 Ta10 Hf15 Al15 (at.%) high entropy alloys. After annealing at 1200 °C for 24 h, the program alloys had a single-phase B2 structure. Further annealing at 600 °C for 24 h resulted in the formation of Widmanstatten orthorhombic particles (O-phase) in the bcc matrix. The Ti40 Nb30 Hf15 Al15 and Ti40 Nb20 Ta10 Hf15 Al15 alloys annealed at T = 1200 °C showed moderate strength and good ductility (>50%) at 22 and 600 °C; while the Ti37.5 Nb12.5 Hf25 Al25 alloy was stronger, but less ductile at both temperatures. Subsequent annealing at T = 600 °C significantly increased the strength of the Ti40 Nb30 Hf15 Al15 alloy at 22 and 600 °C, maintaining compressive sufficient ductility at room-temperature.