First principles investigations of Ta4 AlX3(X= B, C, N) MAX phase ceramics

Abstract

Ta4AlX3 (X=B, C, N) MAX phase ceramics have been examined using first principlescalculations in this study. Ta4AlX3 MAX phase ceramics have hexagonal crystalstructure and the formation energies have been determined for the optimizedcrystal structures. The elastic constants of Ta4AlX3 MAX phase ceramics havebeen determined and these constants satisfy the mechanical stability criteria. Inaddition, the mechanical properties such as bulk modulus, shear modulus, etc.have been obtained to reveal the detailed properties of these compounds. Theanisotropic elastic properties have been visualized in both 3D and 2D. Moreover,the thermal properties of Ta4AlX3 MAX phase ceramics such as thermal expansioncoefficient, heat capacity etc. have been studied in 0 to 1000 K temperature rangeand 0 to 40 GPa pressure range. In this study, Ta4AlB3 has been considered forthe first time along with Ta4AlC3 and Ta4AlN3 compounds and the effect of X atomto the properties of these compounds have been discussed in detail.