Newly Synthesized Ta‐Based MAX Phase (Ta1−xHfx)4AlC3 and (Ta1−xHfx)4Al0.5Sn0.5C3 (0 ≤ x ≤ 0.25) Solid Solutions: Unravelling the Mechanical, Electronic, and Thermodynamic Properties

Abstract

Investigation of the mechanical, electronic, and thermodynamic properties of recently synthesized (Ta1−xHfx)4AlC3 and (Ta1−xHfx)4Al0.5Sn0.5C3 (0 ≤ x ≤ 0.25) solid solutions is conducted using density functional theory for the first time. The computed lattice constants are in good agreement with prior results. The calculated stiffness constants are used to check the mechanical stability of the studied compositions. The bulk modulus (B), shear modulus (G), and Young's modulus (Y) are found to be influenced by Hf and Sn substitution. The titled solid solutions are brittle in nature. The 3D presentations of elastic moduli and elastic anisotropy factors are used to disclose the anisotropic mechanical features of the considered compositions. The electronic band structure, density of states, and charge density mapping (CDM) show the metallic nature, the contribution from different states to electronic conductivity, and atomic bonding characteristics. The electronic band structure and CDM are also used together to investigate the change in bonding strength due to Hf and Sn substitutions. The Debye temperature (ΘD), minimum thermal conductivity (Kmin), Grüneisen parameter (γ), and melting temperature (Tm) of the studied solid solutions are estimated and analyzed. A good correlation is found between the mechanical and thermodynamic properties.