The mechanical properties of (NbMoTaW)Si₂ from a first-principles calculations

Abstract

The realm of ceramic materials has seen a surge in interest directed towards high entropy disilicides due to their exceptional properties. Using the methodologies of density functional theory (DFT) and the special quasi-random structure (SQS), we have delved into the examination of structural stability and the inherent elastic properties of (NbMoTaW)Si2. The available experimental data and the optimized lattice parameters coincide very well. The thermodynamic stability observed in all high entropy ceramics, specifically (NbMoTaW)Si2 disilicides, can be attributed to their negative formation enthalpies. The present results of elastic parameters show that the strength/hardness of (NbMoTaW)Si2 are larger due to the higher bulk and shear moduli. The Vickers hardness of (NbMoTaW)Si2 is higher than the average value of component binary metal silicide, indicating solid solution strengthening effect. The mechanical anisotropy of the (NbMoTaW)Si2 reveals the significant difference in various directions on different crystalline planes. Conducting theoretical research holds significance in facilitating the synthesis of enhanced high entropy disilicides ceramics. Furthermore, such studies are crucial in advancing the evolution and practical utilization of high entropy materials.