Theoretical investigation of the physical characterization of the ordered MAX phase metallic ceramic Mo2Ti2AlC3

Abstract

The first-principles calculations based on the density functional theory were employed to explore the electronic structure, bonding nature, mechanical behavior, and thermodynamic characterization of the newly synthesized 413 MAX phase metallic ceramic Mo2Ti2AlC3. The ground-state crystal structure of Mo2Ti2AlC3 was predicted and the results show that its structure was in agreement with published experimental and theoretical data. The density of states, Mulliken population, and charge density difference map were investigated, and the results reveals that Mo2Ti2AlC3 has a metallic character, and the bonding nature is a mixture of metallic and covalent bonds, which is consistent with that of other MAX materials. The mechanical stability has been verified utilizing the generalized Born-Huang criterion. The mechanical analysis reveals that Mo2Ti2AlC3 is brittle, has a low Vickers hardness (7.3 GPa), and exhibits elastic anisotropy characteristics. Finally, the predicted Debye temperatures, total thermal conductivity, and melting temperature are 726.2 K, 15.31 Wm−1K−1, and 2275.5 K, respectively. Mo2Ti2AlC3 is a potential choice for use in high-temperature scenarios due to its high melting temperature and low thermal conductivity.