Study of the structural, mechanical and thermodynamic properties of the new MAX phase compounds (Zr1-xTix)3AlC2

Abstract

The structural, electronic, mechanical and the thermodynamic properties of the MAX phases (Zr1-xTix)3AlC2 compounds have been investigated by using the full-potential plane-wave FP-LAPW method as implemented in the Wien2k code. The exchange-correlation (XC) energy of electrons was treated using the Perdew–Burke–Ernzerhof parametrization. The ground-state properties for the studied compounds were calculated and compared with available experimental and theoretical data. The calculated lattice parameters are reasonably comparable with experimental and theoretical results. The formation energy has been evaluated in order to determinate the stability of our compounds. The calculation of the electronic structure was predicted for the first time for the present MAX phase compounds. These results indicate that, all our compounds exhibit metallic behavior and this metallicity is due to the p-d hybridization. The elastic constants have also evaluated by the Hex-elastic package. The mechanical stability reveal that, all our compounds are stable mechanically. The bulk modulus, shear modulus, Young’s modulus, Poisson’s ratio and Cauchy pressure were calculated and discussed in detail. Furthermore, the temperature and pressure effect on: Bulk modulus, Debye temperature and heat capacity at constant volume and constant pressure CV and CP, respectively have been investigated by the quasi-harmonic Debye model.