Microstructure, Mechanical Properties and Corrosion Resistance of the Mo0.5V0.5NbTiZrx High-Entropy Alloys with Low Thermal Neutron Sections

Abstract

High-entropy alloys exhibit significant potential for application in the nuclear industry owing to their exceptional resistance to irradiation, excellent mechanical properties, and corrosion resistance. In this work, the Mo_0.5V_0.5NbTiZr_x (x = 0–2.0) high-entropy alloys containing alloying elements with low thermal neutron absorption cross section were designed and prepared. The crystal structure, microstructure, mechanical properties and corrosion resistance of the studied alloys were investigated. All the alloys possess a body-centered cubic crystal structure, which is consistent with the CALPHAD (acronym of CALculation of PHAse Diagram) modeling results. The addition of Zr does not alter the crystal structure of the Mo_0.5V_0.5NbTiZr_x alloys; however, it leads to an increase in the lattice constant as Zr content increases. The addition of Zr initially enhances the yield strength, but subsequently leads to a decline as the Zr content increases further. Specifically, the corrosion resistance of the Mo_0.5V_0.5NbTiZr_x alloys in superheated steam at 400 °C and 10.3 MPa decreases with the increase of Zr content. The effect of Zr content on the phase formation, mechanical properties and corrosion resistance of the Mo_0.5V_0.5NbTiZr_x high-entropy alloys are discussed. This study has successfully developed a novel Mo_0.5V_0.5NbTiZr_0.25 high-entropy alloy, which demonstrates exceptional properties including high yield strength, excellent ductility, and superior anti-corrosion performance. The findings of this research have significant implications for the design of high-entropy alloys in nuclear applications.