Aging behavior of the HfNbTaTiZr high entropy alloy

The HfNbTaTiZr high entropy alloy was produced by vacuum arc melting, homogenized at 1200 °C, and annealed at 600-1000 °C for 1-100 h. Structure and microhardness of the annealed alloy were investigated. A strong increase of microhardness after aging treatment at 600 °C was found. Formation of second hcp phase particles in the bcc matrix after annealing at 600 and 800 °C was also revealed. Effect of precipitation of second phase particles on microhardness was analyzed.