Prediction of mechanical and thermo-physical properties of (Nb-Ti-V-Zr)C high entropy ceramics: A first principles study

Abstract

Effect of different components on structural, mechanical, thermo-physical properties of (Nb-Ti-V-Zr)C crystalline high entropy ceramics (CHECs) were investigated systematically via performing first principles calculations combined with quasi-harmonic Debye-Grüneisen model. The equilibrium lattice constants and density were evaluated by fitting third-order Birch-Murnaghan equation of state. Based on virtual crystal approximation (VCA) method, elastic moduli and lattice constant were consistent with the results from previous theoretical study and experiments, indicating VCA scheme was suitable for random (Nb-Ti-V-Zr)C CHECs. Then various of thermo-physical properties including volumetric thermal expansion coefficient α, constant volume heat capacity and bulk modulus as a function of temperature were calculated by applying quasi-harmonic Debye-Grüneisen model. In finality, the influence of the concentration of differ rent metallic elements on thermo-physical properties were discussed in detail.