AUTHOR=Hu Wenqiang , Pan Min , Huang Zheng , Yang Hongwei , Wu Hao , Pan Liu , Cao Zelin , Zhao Yong TITLE=The Stability and Elasticity in Ta-Ti-V Medium-Entropy Alloys Using First-Principles Calculations JOURNAL=Frontiers in Materials VOLUME=8 YEAR=2021 URL=https://www.frontiersin.org/journals/materials/articles/10.3389/fmats.2021.651435 DOI=10.3389/fmats.2021.651435 ISSN=2296-8016 ABSTRACT=

Due to the low neutron activity, the high thermal stability, and the good compression strength at elevated temperatures, medium-entropy Ta-Ti-V alloys have the application potential to be used in future nuclear engineering. According to experimental results, a special quasi-random structure (SQS) model and first-principles calculations are used to calculate the structural stability and the elasticity of the ternary single-phase body-centered cubic (BCC) Ta-Ti-V alloys with the compositions Ta₂₄Ti₁₄V₁₆, Ta₁₉Ti₁₇V₁₈, Ta₁₆Ti₂₁V₁₇, Ta₂₂Ti₂₃V₉, and Ta₁₈Ti₁₈V₁₈. The mixing energy of five compositions is positive, which indicates that they are unstable at low temperature but stable at high temperature. Meanwhile, we predict the ability of elasticity in those five compositions, and the sequence of bulk modulus is Ta₂₄Ti₁₄V₁₆ > Ta₁₉Ti₁₇V₁₈ > Ta₁₈Ti₁₈V₁₈ > Ta₁₆Ti₂₁V₁₇ > Ta₂₂Ti₂₃V₉ and ductility is Ta₁₉Ti₁₇V₁₈ > Ta₁₈Ti₁₈V₁₈ > Ta₂₂Ti₂₃V₉ > Ta₂₄Ti₁₄V₁₆ > Ta₁₆Ti₂₁V₁₇. Additionally, the influence of the element content on elastic properties shows that the Ta content will increase the bulk modulus of the alloys, while Ti content decreases the bulk modulus. Higher V and Ti contents are beneficial to ductility, especially the V content. The higher Ta content will sharply reduce the ductility of the alloys. Our calculation has provided further theoretical mechanism for the Ta-Ti-V medium-entropy alloys (MEAs) preparation and development.