First Principles Investigations of Ta4AlX3 (X= B, C, N) MAX Phase Ceramics

Ta 4 AlX 3 (X=B, C, N) MAX phase ceramics have been examined using first principles calculations in this study.Ta 4 AlX 3 MAX phase ceramics have hexagonal crystal structure and the formation energies have been determined for the optimized crystal structures.The elastic constants of Ta 4 AlX 3 MAX phase ceramics have been determined and these constants satisfy the mechanical stability criteria.In addition, the mechanical properties such as bulk modulus, shear modulus, etc. have been obtained to reveal the detailed properties of these compounds.The anisotropic elastic properties have been visualized in both 3D and 2D.Moreover, the thermal properties of Ta 4 AlX 3 MAX phase ceramics such as thermal expansion coefficient, heat capacity etc. have been studied in 0 to 1000 K temperature range and 0 to 40 GPa pressure range.In this study, Ta 4 AlB 3 has been considered for the first time along with Ta 4 AlC 3 and Ta 4 AlN 3 compounds and the effect of X atom to the properties of these compounds have been discussed in detail.