mechanical properties

microstructure mechanical

entropy alloy

tial alloy

oxide dispersion strengthened

ti alloy

high entropy

phase

master alloy

porous titanium

International Journal of Refractory Metals and Hard Materials

This study reports the structure and mechanical properties of a new refractory Ti 40 Nb 30 Hf 15 Al 15 (at.%) high entropy alloy. The alloy was fabricated by vacuum arc melting and had a density of 7.07 ± 0.03 g/cm 3 . After annealing at 1200 °C for 24 h, the alloy possessed a single-phase B2 structure. Further annealing at 600 °C for 24 h resulted in the formation of Widmanstatten (Ti, Al)-rich orthorhombic particles (O-phase) in a bcc matrix. The single-phase B2 alloy demonstrated high (>50%) compressive ductility and a pronounced work hardening capacity. The precipitation of the O-phase particles led to a 50% strength increment at 22 and 600 °C, with some sacrificing in the compressive ductility at 22 °C. The obtained results suggest new approaches to the development of precipitation-strengthened refractory high entropy alloys with a balanced combination of the room- and high-temperature properties. • A new Ti 40 Nb 30 Hf 15 Al 15 (at.%) refractory high-entropy alloy was produced. • After annealing at 1200 °C, the alloy had a single-phase B2 phase structure. • Annealing at 600 °C led to precipitation of orthorhombic phase particles in a bcc matrix. • The single-phase B2 alloy demonstrated very high compressive ductility at 22 and 600 °C. • The orthorhombic phase particles drastically increased strength both at 22 and 600 °C.

A new refractory Ti-Nb-Hf-Al high entropy alloy strengthened by orthorhombic phase particles