MAX phase borides, the potential alternative of well-known MAX phase carbides: A case study of V2AB [A = Ge, P, Tl, Zn] via DFT method

Abstract

This study predicted four new MAX phase borides via the DFT method, with a comprehensive and thorough approach. The stability of the predicted phases has been thoroughly studied using formation energy, phonon dispersion curve (PDC), and elastic constants (C_ij). The metallic nature of the studied phases is confirmed through the computation of the electronic band structure and density of states (DOS). Their bonding nature is disclosed using the partial density of states, Mulliken population analysis, and charge density mapping. The mechanical behavior is investigated in depth by calculating elastic constants, elastic moduli, Poisson's & Pugh ratio, machinability index, and Vickers hardness. Different anisotropic indices are also computed to demonstrate the elastic anisotropy. The Debye temperature (Θ_D), Grüneisen parameter (γ), phonon thermal conductivity (k_ph), minimum thermal conductivity (k_min), thermal expansion coefficient (TEC), and melting temperature (T_m) are all calculated, and the suitability of the studied phases as thermal barrier coating (TBC) materials has been discussed. Finally, the optical constants are calculated and analyzed, further certifying the metallic nature of the herein-studied phases. The reflectivity spectra of all the herein selected compounds reveal their potential as coating materials to lessen solar heating. Among the studied phases, V₂PB exhibits the best thermo-mechanical properties for potential applications in diverse fields, such as structural components and TBC materials. The potential applications of our findings are vast, and the obtained results reveal that the predicted phases are indeed potential alternatives to their counterpart carbides.