First-principle Study on Physical Properties and Vacancy Formation of Face-Centered Cubic Co–Ni–Cu–Mo–W High Entropy Alloys

This paper investigated the physical properties and vacancy formation of face-centered cubic (FCC) Co-Ni-Cu-Mo-W high-entropy alloys (HEAs) using first-principle calcula-tion. Firstly, we analyzed the effect of W and Cu content on the physical properties of al-loys. The calculation results show that increasing W content increased the thermodynamic stability, dislocation-energy factor and dislocation width of Co-Ni-Cu-Mo-W HEAs. The fracture energy increased with increasing W atoms at the fracture interface. However, the coefficient of thermal expansion of HEAs decreased with increasing W content. The effect of Cu on the physical properties of Co-Ni-Cu-Mo-W HEAs was contrary to that of the W element. Secondly, we investigated the effect of neighboring atoms on vacancy formation energy (Evf) of Co-Ni-Cu-Mo-W alloys. The results show that the Evf increased with more first-neighboring W and Mo atoms, and the Evf decreased with more first-neighboring Cu atoms. Lastly, we investigated the partial electronic density of state (PDOS) of the first-neighboring atoms before and after forming vacancy. The PDOS in sites with higher Evf changed more obviously after forming vacancy compared with the sites with lower Evf , which indicate that the atoms at higher Evf site have strong bonding effect with neigh-boring atoms.(c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).