Phase Evolution and Mechanical Properties of Low-Activation Refractory High-Entropy Alloy Ti1.5ZrV0.5Ta0.5

A novel low-activation Ti1.5ZrV0.5Ta0.5 refractory high-entropy alloy (RHEA) was designed as a potential candidate for nuclear reactor application. At room temperature, it had an elongation of 8.4% and a yield strength of 1096 MPa. The phase evolution of this alloy and its effect on properties was investigated. At 400 & DEG;C, the solid solution bcc1 transformed into the fcc phase and bcc2 phase, and the & omega; phase and & alpha; phase also appeared. At 600 & DEG;C, the & omega; phase and & alpha; phase disappeared, and the microstructure of the alloy was composed of the fcc phase and bcc2 phase. When the temperature was up to 1200 & DEG;C, the fcc phase and bcc2 phase re-transformed into solid solution bcc1 phase. The precipitation of & omega; phase and & alpha; phase caused a sharp increase in strength and a decrease in plasticity. Meanwhile, the appearance of the fcc phase led to a simultaneous decrease in strength and ductility, due to larger stress concentrations at the fcc/bcc interface. Besides, the formation mechanism of each phase in the alloy was discussed in detail.& COPY; 2023 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.