Microstructure and mechanical properties of HfZrTiNbx high-entropy alloys

HfZrTiNb x (x = 0.25, 0.50, 0.75, 1.00, and 1.25 at. %) high-entropy alloys were prepared using a vacuum arc furnace, and their phase composition and tensile properties were investigated. The results showed that the HfZrTiNb 0.25 and HfZrTiNb 0.50 alloys consisted of β phase, α phase, and ω phase, while the other alloys were composed of β phase. The yield strength of the HfZrTiNb 0.25 alloy was 817 MPa, but its elongation at break was 1.4%, which was attributed to the presence of the α phase. As the Nb content increased, the alloy's ductility also improved, with the HfZrTiNb 1.25 alloy exhibiting an elongation at break of 20.5%. The primary reason for the excellent ductility of this alloy was the increased dislocation density and entangled dislocations.