A comparative first-principles study of the electronic, mechanical, defect and acoustic properties of Ti₂AlC and Ti₃AlC

Recently synthesized (Ti1−xMox)2AlC (0 ≤ x ≤ 0.20) solid solutions: deciphering the structural, electronic, mechanical and thermodynamic properties via ab initio simulations

“…The calculated lattice constants of Ti 2 AlC, a and c are just 0.29% and 0.69%, respectively higher than the experimental values 71 and also comparable with the reported values of the parent phase Ti 2 AlC. [72][73][74][75] This demonstrates high level of reproducibility and reliability of our calculations. The nonexistence of energy band gap in the electronic band structure and nite DOS ($3.0 states per eV) at the Fermi level clearly reveal the metallic nature of the studied solid solutions where the electrical conductivity is expected to be strongly anisotropic.…”

“…Optimized lattice constants are presented in Table 1 together with values obtained by others. [71][72][73][74][75] The calculated ground state lattice constants of Ti 2 AlC: a and c are just 0.29% and 0.69%, respectively, higher than the experimentally obtained values. This ensures very high level of consistency of present rst-principles calculations.…”

“…The computed stiffness constants (C ij ) and polycrystalline elastic constants and ratios (B, G, Y, G/B and y) are found in good accord with the reported values (for x ¼ 0.0). 56,72,74,[81][82][83] The mechanical stability of the studied solid solutions is validated by Born criteria based on the values of C ij . The single crystal elastic constants (C 11 , C 33 and C 44 ) and other mechanical parameters of studied solid solutions are found to be increased by a considerable extent owing to Mo substitution for Ti which suggests enhanced mechanical hardness for the same.…”

Ab initio predictions of structure and physical properties of the Zr2GaC and Hf2GaC MAX phases under pressure

“…The conduction bands overlap with the valance band at the Fermi level without having a bandgap in the vicinity of the Fermi level resulting in the metallic behavior of the M 2 GaC MAX phase compounds. Moreover, band structures' appearance resembles other metallic MAX phases, i.e., Cr 2 AlC 73 and Ti 2 AlC 74 . The small energy dispersion along the K–H and L–M directions indicates the strong anisotropic behavior.…”

DFT Study of MAX Phase Surfaces for Electrocatalyst Support Materials in Hydrogen Fuel Cells

“…Point defect vacancies have been more extensively studied in the literature for Ti 2 AlC [ 18 , 19 , 20 , 21 ] and for Ti 3 AlC 2 and Ti 3 SiC 2 [ 22 , 23 , 24 , 25 , 26 ]. There is consensus that the A-group atom in MAX phases has the lowest vacancy formation energy, which agrees with the experimental results [ 27 , 28 , 29 , 30 ] showing that oxides of the A-element form on the surface during oxidation, e.g., Al 2 O 3 and SiO 2 .…”