Effect of carbon on microstructure and mechanical properties of TiZrNb _0.5 V _0.5 lightweight refractory high entropy alloy

The single-phase body-centered cubic TiZrNb 0.5 V 0.5 lightweight refractory high entropy alloy exhibits good plasticity but poor strength. Therefore, C is added to this alloy to enhance its strength and improve its mechanical properties in this paper. The influence of varying C content on the microstructure, phase composition, and mechanical behavior of TiZrNb 0.5 V 0.5 C x RHEAs is investigated in detail. The results indicate that C addition leads to the dissolution of alloying dendrites and induces the formation of the FCC – MC carbides phase. The carbide volume fraction increases in proportion to the carbon content, thereby enhancing the alloy's yield strength and hardness. The yield strength increases by 36%, while the hardness increases by 39%. The physical parameters of the alloy are analyzed, which reveals that the introduction of C increases the alloy's electronegativity and atomic radius difference, thus promoting the formation of carbides.