Composition Design, Microstructures Evolution and Properties of Low-Activation Single-Phase Fe36.41Cr28.06V35.53 Medium-Entropy Alloys

According to the requirements of low activation materials and reducing cost, Fe, Cr and V elements are selected to design a single-phase medium entropy alloy with non-equal atomic ratio of Fe36.41Cr28.06V35.53 based on minimizing Gibbs free energy. The alloys were synthesized by vacuum melting method followed by hot-rolling and heat treatments. It is found that Fe36.41Cr28.06V35.53 alloy is single-phase bcc solid solution in different treatment states. No any phase transformation is detected. It reveals that the phase structure of the alloy is quite stable, which is in good agreement with the design results. The hardness of the Fe36.41Cr28.06V35.53 alloy is higher than that of the traditional heat-resistant alloys, and the compressive plasticity of the alloys in different treatment states is more than 50%, which achieves a good match of strength and plasticity. Due to the interaction between segregation elements and dislocations, the compressive stress-strain curve of the alloy exhibits serrated flow behavior during the compression deformation process. The microstructures of the Fe36.41Cr28.06V35.53 alloy were characterized in details, and the mechanism of the excellent properties for the alloy was also explained.